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()

    val serverSocket = ServerSocket(0, 1, localhost)

    val socket = Socket()
    socket.connect(serverSocket.localSocketAddress)
    val socketSource = socket.source().buffer()

    assertThat(socket.isHealthy(socketSource)).isTrue()

    serverSocket.close()
    assertThat(socket.isHealthy(socketSource)).isFalse()
  }

  @Test
  fun testDurationTimeUnit() {

  }

  override fun createSocket(): Socket =
    object : Socket() {
      override fun connect(
        endpoint: SocketAddress?,
        timeout: Int,
      ) {
        val requested = (endpoint as InetSocketAddress)
        val inetSocketAddress = hostMapping[requested.address] ?: defaultAddress ?: requested
        Platform.get().log("Socket connection to: $inetSocketAddress was: $requested")

             * because we might close the socket during a
             * request. However the chances are slim and the
             * retry code should ensure the overall request
             * is serviced. The alternative complicates things
             * more than I think is worth it.
             */

            if (socket != null) {
                socket.close();
                socket = null;
            }

  /** 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

   * 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

      .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()
      }
    }
  }

      serverSocketChannel.configureBlocking(true);
      serverSocketChannel.socket().bind(address);
    }

    @Override public int getLocalPort() {
      return 1; // A white lie. There is no local port.
    }

    @Override public SocketAddress getLocalSocketAddress() {
      return endpoint;
    }

    @Override public Socket accept() throws IOException {
      try {

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.

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