@Throws(IOException::class)
  @JvmOverloads
  fun start(sendConnectionPreface: Boolean = true) {
    if (sendConnectionPreface) {
      writer.connectionPreface()
      writer.settings(okHttpSettings)
      val windowSize = okHttpSettings.initialWindowSize
      if (windowSize != DEFAULT_INITIAL_WINDOW_SIZE) {
        writer.windowUpdate(0, (windowSize - DEFAULT_INITIAL_WINDOW_SIZE).toLong())
      }
    }

  /** True if response headers have been sent or received. */
  private var hasResponseHeaders: Boolean = false

  override val source =
    FramingSource(
      maxByteCount = connection.okHttpSettings.initialWindowSize.toLong(),
      finished = inFinished,
    )
  override val sink =
    FramingSink(
      finished = outFinished,
    )
  internal val readTimeout = StreamTimeout()