*/
  private var trailers: Headers? = null

  /** Returns true if this connection is closed. */
  val isClosed: Boolean
    get() = state == STATE_CLOSED

  override fun createRequestBody(
    request: Request,
    contentLength: Long,
  ): Sink {
    return when {
      request.body?.isDuplex() == true -> throw ProtocolException(
        "Duplex connections are not supported for HTTP/1",
      )