* closing, closed, or canceled.
   *
   * This method returns immediately.
   */
  fun send(bytes: ByteString): Boolean

  /**
   * Attempts to initiate a graceful shutdown of this web socket. Any already-enqueued messages will
   * be transmitted before the close message is sent but subsequent calls to [send] will return
   * false and their messages will not be enqueued.
   *

        // Assume the server won't send a TLS ServerHello until we send a TLS ClientHello. If
        // that happens, then we will have buffered bytes that are needed by the SSLSocket!
        // This check is imperfect: it doesn't tell us whether a handshake will succeed, just
        // that it will almost certainly fail because the proxy has sent unexpected data.

     */
    protected Curl() {
        // nothing
    }

    /**
     * Creates a new CurlRequest with the HTTP GET method for the specified URL.
     *
     * @param url the URL to send the GET request to
     * @return a CurlRequest object configured with the GET method and the specified URL
     */
    public static CurlRequest get(final String url) {
        return new CurlRequest(Method.GET, url);
    }

    /**
     * Apply inbound settings and send an acknowledgement to the peer that provided them.
     *
     * We need to apply the settings and ack them atomically. This is because some HTTP/2
     * implementations (nghttp2) forbid peers from taking advantage of settings before they have
     * acknowledged! In particular, we shouldn't send frames that assume a new `initialWindowSize`
     * until we send the frame that acknowledges this new size.

     * @param debugData only valid for HTTP/2; opaque debug data to send.
     */
    fun goAway(
      lastGoodStreamId: Int,
      errorCode: ErrorCode,
      debugData: ByteString,
    )

    /**
     * Notifies that an additional `windowSizeIncrement` bytes can be sent on `streamId`, or the
     * connection if `streamId` is zero.
     */
    fun windowUpdate(

    been received. Previously these events were incorrectly sent too early, when OkHttp was ready to
    read the response headers or body, which mislead tracing tools. Note that the `responseFailed()`
    event always used to follow one of these events; now it may be sent without them.

 *  New: Upgrade to Kotlin 1.3.61.

   * sent.
   */
  private fun recover(
    e: IOException,
    call: RealCall,
    userRequest: Request,
  ): Boolean {
    val requestSendStarted = e !is ConnectionShutdownException

    // The application layer has forbidden retries.
    if (!client.retryOnConnectionFailure) return false

    // We can't send the request body again.

   * received without TLS.
   */
  public val handshake: Handshake?,
  /**
   * Returns the name of the server the client requested via the SNI (Server Name Indication)
   * attribute in the TLS handshake. Unlike the rest of the HTTP exchange, this name is sent in
   * cleartext and may be monitored or blocked by a proxy or other middlebox.
   */
  public val handshakeServerNames: List<String>,

      object : RecordingEventListener() {
        override fun responseHeadersEnd(
          call: Call,
          response: Response,
        ) {
          try {
            // Wait for the server to send the duplex response before acting on the 301 response
            // and resetting the stream.
            duplexResponseSent.await()
          } catch (e: InterruptedException) {
            throw AssertionError()

        .receivedResponseAtMillis(receivedResponseMillis)
        .build()
    }

    companion object {
      /** Synthetic response header: the local time when the request was sent. */
      private val SENT_MILLIS = "${Platform.get().getPrefix()}-Sent-Millis"

      /** Synthetic response header: the local time when the response was received. */
      private val RECEIVED_MILLIS = "${Platform.get().getPrefix()}-Received-Millis"
    }