fun upgradeToSocket(): Socket {
    call.upgradeToSocket()
    (codec.carrier as RealConnection).useAsSocket()

    return object : Socket {
      override fun cancel() {
        ******@****.***()
      }

      override val sink =
        RequestBodySink(
          delegate = codec.socket.sink,
          contentLength = -1L,
          isSocket = true,
        )

    sequenceNumber: Int,
    socket: Socket,
    failure: IOException? = null,
  ) {
    this.requestLine = requestLine
    this.headers = headers
    this.chunkSizes = chunkSizes
    this.bodySize = bodySize
    this.body = body
    this.sequenceNumber = sequenceNumber
    this.failure = failure

    if (socket is SSLSocket) {
      try {
        this.handshake = socket.session.handshake()

  /** Returns the route used by this connection. */
  fun route(): Route

  /**
   * Returns the socket that this connection is using. Returns an
   * [SSL socket][javax.net.ssl.SSLSocket] if this connection is HTTPS. If this is an HTTP/2
   * connection the socket may be shared by multiple concurrent calls.
   */
  fun socket(): Socket

  /**
   * Returns the TLS handshake used to establish this connection, or null if the connection is not

      .build()

  class SocketClosingEventListener : EventListener() {
    var shouldClose: Boolean = false
    var lastSocket: Socket? = null

    override fun connectionAcquired(
      call: Call,
      connection: Connection,
    ) {
      lastSocket = connection.socket()
    }

    override fun requestHeadersStart(call: Call) {
      if (shouldClose) {
        lastSocket!!.close()
      }
    }
  }

We can't rely on application threads to read data from the socket. Application threads are transient: sometimes they're reading and writing and sometimes they're off doing application-layer things. But the socket is permanent, and it needs constant attention: we dispatch all incoming frames so the connection is good-to-go when the application layer needs it.

So we have a dedicated thread for every socket that just reads frames and dispatches them.

   * after the response and will close the connection when the client's socket is exhausted.
   *
   * On HTTP/1 this closes the socket.
   */
  public object ShutdownConnection : SocketEffect

  /**
   * On HTTP/2 this will send the error code on the stream.
   *
   * On HTTP/1 this closes the socket.
   */
  public class CloseStream(
    public val http2ErrorCode: Int = 0,
  ) : SocketEffect

      }

    /**
     * Sets the socket factory used to create connections. OkHttp only uses the parameterless
     * [SocketFactory.createSocket] method to create unconnected sockets. Overriding this method,
     * e. g., allows the socket to be bound to a specific local address.
     *
     * If unset, the [system-wide default][SocketFactory.getDefault] socket factory will be used.
     */

  ): RealConnection {
    val result =
      RealConnection.newTestConnection(
        taskRunner = taskRunner,
        connectionPool = pool,
        route = route,
        socket = Socket(),
        idleAtNs = idleAtNanos,
      )
    result.withLock { pool.put(result) }
    return result
  }

  fun newConnectionPool(
    taskRunner: TaskRunner = this.taskRunner,

import okio.Sink
import okio.Socket
import okio.Source

/** Encodes HTTP requests and decodes HTTP responses. */
interface ExchangeCodec {
  /** The connection or CONNECT tunnel that owns this codec. */
  val carrier: Carrier

  /** Returns true if the response body and (possibly empty) trailers have been received. */
  val isResponseComplete: Boolean

  /** The socket that carries this exchange. */
  val socket: Socket

    val port = fromSource.readShort() and 0xffff

    when (command) {
      COMMAND_CONNECT -> {
        val toSocket = Socket(toAddress, port)
        val localAddress = toSocket.localAddress.address
        if (localAddress.size != 4) {
          throw ProtocolException("unexpected address: " + toSocket.localAddress)
        }

        // Write the reply.
        fromSink.writeByte(VERSION_5)