Here we `POST` a request body as a stream. The content of this request body is being generated as it's being written. This example streams directly into the [Okio](https://github.com/square/okio) buffered sink. Your programs may prefer an `OutputStream`, which you can get from `BufferedSink.outputStream()`.

=== ":material-language-kotlin: Kotlin"
    ```kotlin
      private val client = OkHttpClient()

import okhttp3.internal.toLongOrDefault
import okio.Buffer
import okio.BufferedSink
import okio.BufferedSource
import okio.ByteString.Companion.decodeBase64
import okio.ByteString.Companion.encodeUtf8
import okio.ByteString.Companion.toByteString
import okio.FileSystem
import okio.ForwardingSink
import okio.ForwardingSource
import okio.Path
import okio.Path.Companion.toOkioPath
import okio.Sink
import okio.Source
import okio.buffer

square-kotlin-poet = { module = "com.squareup:kotlinpoet", version.ref = "square-kotlin-poet" }
square-okio = { module = "com.squareup.okio:okio", version.ref = "square-okio" }
square-okio-fakefilesystem = { module = "com.squareup.okio:okio-fakefilesystem", version.ref = "square-okio" }
testcontainers = { module = "org.testcontainers:testcontainers", version.ref = "testcontainers" }

import okhttp3.mockwebserver.Dispatcher;
import okhttp3.mockwebserver.MockResponse;
import okhttp3.mockwebserver.MockWebServer;
import okhttp3.mockwebserver.RecordedRequest;
import okio.Buffer;
import okio.Okio;

public class SampleServer extends Dispatcher {
  private final SSLContext sslContext;
  private final String root;
  private final int port;

import okhttp3.internal.http2.Header.Companion.TARGET_PATH
import okhttp3.internal.http2.Header.Companion.TARGET_SCHEME
import okhttp3.internal.unmodifiable
import okio.Buffer
import okio.BufferedSource
import okio.ByteString
import okio.Source
import okio.buffer

/**
 * Read and write HPACK v10.
 *
 * http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-12
 *

  id("okhttp.testing-conventions")
}

project.applyJavaModules("okhttp3.mockwebserver")

dependencies {
  "friendsApi"(projects.okhttp)
  api(projects.mockwebserver3)
  api(libs.junit)
  api(libs.square.okio)

  testImplementation(projects.okhttpTestingSupport)
  testImplementation(projects.okhttpTls)
  testImplementation(libs.kotlin.test.common)
  testImplementation(libs.kotlin.test.junit)

import okhttp3.internal.connection.ConnectionListener
import okhttp3.internal.platform.Platform
import okhttp3.testing.PlatformRule
import okio.BufferedSink
import okio.ForwardingFileSystem
import okio.IOException
import okio.Path
import okio.Path.Companion.toPath
import okio.fakefilesystem.FakeFileSystem
import org.junit.jupiter.api.Test
import org.junit.jupiter.api.extension.RegisterExtension

@Burst

import okhttp3.internal.http2.Http2.frameLog
import okhttp3.internal.http2.Http2.frameLogWindowUpdate
import okhttp3.internal.readMedium
import okio.Buffer
import okio.BufferedSource
import okio.ByteString
import okio.Source
import okio.Timeout

/**
 * Reads HTTP/2 transport frames.
 *
 * This implementation assumes we do not send an increased [frame][Settings.getMaxFrameSize] to the

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.internal.http1

import okhttp3.Headers
import okhttp3.internal.HEADER_LIMIT
import okio.BufferedSource

/**
 * Parse all headers delimited by "\r\n" until an empty line. This throws if headers exceed 256 KiB.
 */
class HeadersReader(
  val source: BufferedSource,
) {

import okhttp3.mockwebserver.SocketPolicy
import okhttp3.tls.HandshakeCertificates
import okhttp3.tls.HeldCertificate
import okhttp3.tls.internal.TlsUtil.localhost
import okio.Buffer
import okio.BufferedSink
import okio.BufferedSource
import okio.ByteString
import okio.Timeout
import org.junit.jupiter.api.AfterEach
import org.junit.jupiter.api.Assumptions.assumeFalse
import org.junit.jupiter.api.BeforeEach