diff --git a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiClient.kt.mustache b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiClient.kt.mustache
index 50adff43789ce9e1147593152b63fc5818e32cc4..32b20282811db473ddf269b780b42b7a827463ea 100644
--- a/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiClient.kt.mustache
+++ b/modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiClient.kt.mustache
@@ -206,22 +206,26 @@ import com.squareup.moshi.adapter
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             {{^supportAndroidApiLevel25AndBelow}}
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.{{packageName}}", null).toFile()
+            val tempFile = java.nio.file.Files.createTempFile("tmp.{{packageName}}", null).toFile()
             {{/supportAndroidApiLevel25AndBelow}}
             {{#supportAndroidApiLevel25AndBelow}}
-            val f = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            val tempFile = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                 java.nio.file.Files.createTempFile("tmp.net.medicineone.teleconsultationandroid.openapi.openapicommon", null).toFile()
             } else {
                 @Suppress("DEPRECATION")
                 createTempFile("tmp.net.medicineone.teleconsultationandroid.openapi.openapicommon", null)
             }
             {{/supportAndroidApiLevel25AndBelow}}
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-array-simple-string-jvm-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-array-simple-string-jvm-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 5b21ddef1c80e3f27ee08887ce0b6d593a475fe5..6db8e7c74f2410caaf5c8122be41e34942f67c22 100644
--- a/samples/client/petstore/kotlin-array-simple-string-jvm-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-array-simple-string-jvm-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -116,12 +116,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-array-simple-string-jvm-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-array-simple-string-jvm-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 3dd90f5f36d41d49a21f255e50fb47d3025c75ad..bfd00ac6a2ef1e61ed4841e5df7f10d41eb97a53 100644
--- a/samples/client/petstore/kotlin-array-simple-string-jvm-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-array-simple-string-jvm-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -118,12 +118,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-bigdecimal-default-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-bigdecimal-default-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 3dd90f5f36d41d49a21f255e50fb47d3025c75ad..bfd00ac6a2ef1e61ed4841e5df7f10d41eb97a53 100644
--- a/samples/client/petstore/kotlin-bigdecimal-default-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-bigdecimal-default-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -118,12 +118,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-default-values-jvm-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-default-values-jvm-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 5b21ddef1c80e3f27ee08887ce0b6d593a475fe5..6db8e7c74f2410caaf5c8122be41e34942f67c22 100644
--- a/samples/client/petstore/kotlin-default-values-jvm-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-default-values-jvm-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -116,12 +116,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-default-values-jvm-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-default-values-jvm-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 3dd90f5f36d41d49a21f255e50fb47d3025c75ad..bfd00ac6a2ef1e61ed4841e5df7f10d41eb97a53 100644
--- a/samples/client/petstore/kotlin-default-values-jvm-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-default-values-jvm-okhttp4/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -118,12 +118,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-enum-default-value/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-enum-default-value/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 3dd90f5f36d41d49a21f255e50fb47d3025c75ad..bfd00ac6a2ef1e61ed4841e5df7f10d41eb97a53 100644
--- a/samples/client/petstore/kotlin-enum-default-value/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-enum-default-value/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -118,12 +118,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 78a723ea49bfff0b1a9c541ad8b9f705878c2b1e..17485b2c88779b3dd13accdecbe933752f0e7929 100644
--- a/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-gson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -117,12 +117,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-jackson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-jackson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index e4f45f28927f2713258b758300d98d482c6a66dc..5040c47697cf0d0ac10350d968c572e7bb9d2606 100644
--- a/samples/client/petstore/kotlin-jackson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-jackson/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -117,12 +117,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index e00657437a975254211612909dcf27d0e0b28486..804c66706c28c5157f0c1447f832c481156af0dd 100644
--- a/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -119,16 +119,20 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
-            val f = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            // return tempFile
+            val tempFile = if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                 java.nio.file.Files.createTempFile("tmp.net.medicineone.teleconsultationandroid.openapi.openapicommon", null).toFile()
             } else {
                 @Suppress("DEPRECATION")
                 createTempFile("tmp.net.medicineone.teleconsultationandroid.openapi.openapicommon", null)
             }
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-jvm-okhttp4-coroutines/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-jvm-okhttp4-coroutines/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index ab05dc14f205467c8ac701297d2c4bf4cb960c5d..cacd2b743b3313ea1ea92d2a09750cc866ec238b 100644
--- a/samples/client/petstore/kotlin-jvm-okhttp4-coroutines/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-jvm-okhttp4-coroutines/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -120,12 +120,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-modelMutable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-modelMutable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index c48bc6a8193332a6bcbb44970e2a66c3cdea17c4..4ad22a02df06c2f03d0bfd1a59ed49121988f704 100644
--- a/samples/client/petstore/kotlin-modelMutable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-modelMutable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -118,12 +118,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index c48bc6a8193332a6bcbb44970e2a66c3cdea17c4..4ad22a02df06c2f03d0bfd1a59ed49121988f704 100644
--- a/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-moshi-codegen/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -118,12 +118,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 1c2e0a93e8a93176bb60d767e547e37ccf4c2fb8..61ba8e30416dac873cb5f2eb409ddc6e25b5f007 100644
--- a/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-nonpublic/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -118,12 +118,16 @@ internal open class ApiClient(val baseUrl: String, val client: OkHttpClient = de
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index c48bc6a8193332a6bcbb44970e2a66c3cdea17c4..4ad22a02df06c2f03d0bfd1a59ed49121988f704 100644
--- a/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-nullable/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -118,12 +118,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index ef5d9840725663c0f5c9e8f3ac7169d779f02770..9fcf1385050513f7e04360d188617fb6ca544c36 100644
--- a/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-okhttp3/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -116,12 +116,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index c48bc6a8193332a6bcbb44970e2a66c3cdea17c4..4ad22a02df06c2f03d0bfd1a59ed49121988f704 100644
--- a/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -118,12 +118,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index d4ea2444ab517e54b3a519c7d015489043441ad1..3d6b7ccb792af4c4774e4f36ade5bd740226f844 100644
--- a/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-threetenbp/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -118,12 +118,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index 3dd90f5f36d41d49a21f255e50fb47d3025c75ad..bfd00ac6a2ef1e61ed4841e5df7f10d41eb97a53 100644
--- a/samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -118,12 +118,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {
diff --git a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
index c48bc6a8193332a6bcbb44970e2a66c3cdea17c4..4ad22a02df06c2f03d0bfd1a59ed49121988f704 100644
--- a/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
+++ b/samples/client/petstore/kotlin/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
@@ -118,12 +118,16 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             return null
         }
         if (T::class.java == File::class.java) {
-            // return tempfile
+            // return tempFile
             // Attention: if you are developing an android app that supports API Level 25 and bellow, please check flag supportAndroidApiLevel25AndBelow in https://openapi-generator.tech/docs/generators/kotlin#config-options
-            val f = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
-            f.deleteOnExit()
-            body.byteStream().use { java.nio.file.Files.copy(it, f.toPath(), java.nio.file.StandardCopyOption.REPLACE_EXISTING) }
-            return f as T
+            val tempFile = java.nio.file.Files.createTempFile("tmp.org.openapitools.client", null).toFile()
+            tempFile.deleteOnExit()
+            body.byteStream().use { inputStream ->
+                tempFile.outputStream().use { tempFileOutputStream ->
+                    inputStream.copyTo(tempFileOutputStream)
+                }
+            }
+            return tempFile as T
         }
         val bodyContent = body.string()
         if (bodyContent.isEmpty()) {