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() {

    val buffer = Buffer()
    body.writeTo(buffer)
    assertThat(buffer.readUtf8()).isEqualTo(expected)
  }

  @Test
  fun streamingPartHasNoLength() {
    class StreamingBody(private val body: String) : RequestBody() {
      override fun contentType(): MediaType? {
        return null
      }

      @Throws(IOException::class)
      override fun writeTo(sink: BufferedSink) {
        sink.writeUtf8(body)

  }

  @Throws(IOException::class)
  override fun contentLength(): Long {
    return delegate.contentLength()
  }

  @Throws(IOException::class)
  override fun writeTo(sink: BufferedSink) {
    delegate.writeTo(sink)
  }

  override fun isDuplex(): Boolean {
    return delegate.isDuplex()
  }

  override fun toString(): String {
    return javaClass.simpleName + "(" + delegate.toString() + ")"

  return object : RequestBody() {
    override fun contentType() = contentType

    override fun contentLength() = byteCount.toLong()

    override fun writeTo(sink: BufferedSink) {
      sink.write(this@commonToRequestBody, offset, byteCount)
    }
  }
}

@Suppress("unused")
fun RequestBody.commonContentLength(): Long = -1L

@Suppress("unused")

  /**
   * 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 = commonContentLength()

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

  /**

    val out = Buffer()
    body.writeTo(out)
    assertThat(out.readUtf8()).isEqualTo(expected)
  }

  @Test
  fun encodedPair() {
    val body =
      FormBody.Builder()
        .add("sim", "ple")
        .build()
    val expected = "sim=ple"
    assertThat(body.contentLength()).isEqualTo(expected.length.toLong())
    val buffer = Buffer()
    body.writeTo(buffer)

      )

    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.

    val uppercaseBody: RequestBody =
      object : ForwardingRequestBody(request.body) {
        @Throws(IOException::class)
        override fun writeTo(sink: BufferedSink) {
          delegate().writeTo(uppercaseSink(sink).buffer())
        }
      }
    return request.newBuilder()
      .method(request.method, uppercaseBody)
      .build()
  }

	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.

            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 {