/**
   * Returns the number of bytes that will be written to sink in a call to [writeTo],
   * or -1 if that count is unknown.
   */
  @Throws(IOException::class)
  open fun contentLength(): Long = -1L

  /** Writes the content of this request to [sink]. */
  @Throws(IOException::class)
  abstract fun writeTo(sink: BufferedSink)

  /**

    assertOnFileDescriptor(content = "Hello") { fd ->
      val requestBody = fd.toRequestBody()

      val buffer = Buffer()
      requestBody.writeTo(buffer)
      assertThat(buffer.readUtf8()).isEqualTo("Hello")

      assertThrows(IOException::class.java) {
        requestBody.writeTo(Buffer())
      }
    }
  }

  @Test
  fun testFileDescriptorAfterClose() {

    override fun contentType() = delegate.contentType()

    @Throws(IOException::class)
    override fun contentLength(): Long = delegate.contentLength()

    @Throws(IOException::class)
    override fun writeTo(sink: BufferedSink) {
      val forwardingSink =
        object : ForwardingSink(sink) {
          private var totalBytesWritten: Long = 0
          private var completed = false

          override fun write(

            requestBody.writeTo(bufferedRequestBody)
          } else {
            // Write the request body if the "Expect: 100-continue" expectation was met.
            val bufferedRequestBody = exchange.createRequestBody(request, false).buffer()
            requestBody.writeTo(bufferedRequestBody)
            bufferedRequestBody.close()
          }
        } else {

) : RequestBody() {
  override fun contentType() = delegate.contentType()

  // We don't know the compressed length in advance!
  override fun contentLength() = -1L

  override fun writeTo(sink: BufferedSink) {
    GzipSink(sink).buffer().use(delegate::writeTo)
  }

  override fun isOneShot() = delegate.isOneShot()

 * called by readers.
 */
public interface MockResponseBody {
  /** The length of this response in bytes, or -1 if unknown. */
  public val contentLength: Long

  @Throws(IOException::class)
  public fun writeTo(sink: BufferedSink)

      )

    call.execute().use { response ->
      assertThat(response.body.string()).isEqualTo("abc")
      val requestBodyOut = requestBody.takeSink()
      assertFailsWith<IOException> {
        SlowRequestBody.writeTo(requestBodyOut)
      }
      assertFailsWith<IOException> {
        requestBodyOut.close()
      }
    }

    // Confirm that the connection pool was not corrupted by making another call.

    @Override
    public long contentLength() throws IOException {
      return delegate.contentLength();
    }

    @Override
    public void writeTo(BufferedSink sink) throws IOException {
      BufferedSink bufferedSink = Okio.buffer(sink(sink));
      delegate.writeTo(bufferedSink);
      bufferedSink.flush();
    }

    public Sink sink(Sink sink) {
      return new ForwardingSink(sink) {

      override fun writeTo(sink: BufferedSink) {
        sink.writeUtf8("<el")
        sink.flush()
        throw IOException("failed to stream the XML")
      }
    }

    class ValidRequestBody : RequestBody() {
      override fun contentType(): MediaType = "application/xml".toMediaType()

      override fun writeTo(sink: BufferedSink) {
        sink.writeUtf8("<element/>")

	if err != nil && err != io.EOF {
		tr.err = err
	}
	return n, err
}

// writeTo writes the content of the current file to w.
// The bytes written matches the number of remaining bytes in the current file.
//
// If the current file is sparse and w is an io.WriteSeeker,
// then writeTo uses Seek to skip past holes defined in Header.SparseHoles,
// assuming that skipped regions are filled with NULs.