}

    /**
     * Attempts to perform a web socket upgrade on the connection.
     * This will overwrite any previously set status, body, or streamHandler.
     */
    fun webSocketUpgrade(listener: WebSocketListener) =
      apply {
        status = "HTTP/1.1 101 Switching Protocols"
        setHeader("Connection", "Upgrade")
        setHeader("Upgrade", "websocket")
        webSocketListener = listener

  }

  @Test
  fun staleConnectionNotReusedForNonIdempotentRequest() {
    // Capture the connection so that we can later make it stale.
    var connection: RealConnection? = null
    client =
      client.newBuilder()
        .addNetworkInterceptor(
          Interceptor { chain ->
            connection = chain.connection() as RealConnection
            chain.proceed(chain.request())
          },
        )

    this.withLock {
      if (closed) throw IOException("closed")
      if (!client) return // Nothing to write; servers don't send connection headers!
      if (logger.isLoggable(FINE)) {
        logger.fine(format(">> CONNECTION ${CONNECTION_PREFACE.hex()}"))
      }
      sink.write(CONNECTION_PREFACE)
      sink.flush()
    }
  }

  /** Applies `peerSettings` and then sends a settings ACK. */
  @Throws(IOException::class)

      }
    } else {
      // The server reads the CONNECTION_PREFACE byte string.
      val connectionPreface = source.readByteString(CONNECTION_PREFACE.size.toLong())
      if (logger.isLoggable(FINE)) logger.fine(format("<< CONNECTION ${connectionPreface.hex()}"))
      if (CONNECTION_PREFACE != connectionPreface) {
        throw IOException("Expected a connection header but was ${connectionPreface.utf8()}")
      }
    }
  }

        Protocol protocol, IOException ioe) {
      printEvent("connectFailed");
    }

    @Override public void connectionAcquired(Call call, Connection connection) {
      printEvent("connectionAcquired");
    }

    @Override public void connectionReleased(Call call, Connection connection) {
      printEvent("connectionReleased");
    }

    @Override public void requestHeadersStart(Call call) {

    clientListener.assertTextMessage("Hello, WebSockets!")
    closeWebSockets(webSocket, server)
  }

  /**
   * We had a bug where web socket connections were leaked if the HTTP connection upgrade was not
   * successful. This test confirms that connections are released back to the connection pool!
   * https://github.com/square/okhttp/issues/4258
   */
  @Test
  @Throws(Exception::class)
  fun webSocketConnectionIsReleased() {

 * Fix: Respect read timeouts on recycled connections.
 * Fix: Transmit multiple cookie values as a single header with delimiter.
 * Fix: Ensure `null` is never returned from a connection's `getHeaderFields()`.
 * Fix: Persist proper `Content-Encoding` header to cache for GZip responses.
 * Fix: Eliminate rare race condition in SPDY streams that would prevent connection reuse.

Content-Type: text/html
Content-Length: 193
Connection: keep-alive
Location: https://publicobject.com/helloworld.txt

INFO: Sending request https://publicobject.com/helloworld.txt on Connection{publicobject.com:443, proxy=DIRECT hostAddress=54.187.32.157 cipherSuite=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA protocol=http/1.1}
User-Agent: OkHttp Example
Host: publicobject.com
Connection: Keep-Alive
Accept-Encoding: gzip

    return null
  }

  override fun connectionReleased(connection: Connection) {
  }

  override fun connectionConnectionAcquired(connection: RealConnection) {
  }

  override fun connectionConnectionReleased(connection: RealConnection) {
  }

  override fun connectionConnectionClosed(connection: RealConnection) {
  }

  override fun noNewExchanges(connection: RealConnection) {
  }

   * HTTP/2 can have both stream timeouts (due to a problem with a single stream) and connection
   * timeouts (due to a problem with the transport). When a stream times out we don't know whether
   * the problem impacts just one stream or the entire connection.
   *
   * To differentiate the two cases we ping the server when a stream times out. If the overall
   * connection is fine the ping will receive a pong; otherwise it won't.
   *