*/
package okhttp3

import java.io.IOException
import java.util.concurrent.TimeUnit

/**
 * Observes, modifies, and potentially short-circuits requests going out and the corresponding
 * responses coming back in. Typically interceptors add, remove, or transform headers on the request
 * or response.
 *
 * Implementations of this interface throw [IOException] to signal connectivity failures. This

    require(length < bytesOut.size - lastFrame.start)

    // Move everything from bytesOut into a new buffer.
    val fullBuffer = Buffer()
    bytesOut.read(fullBuffer, bytesOut.size)

    // Copy back all but what we're truncating.
    fullBuffer.read(bytesOut, lastFrame.start + length)
    outFrames.add(OutFrame(lastFrame.sequence, lastFrame.start, true))
    return writer
  }

    server.enqueue(MockResponse(body = "this response comes via SSL"))
    client =
      client.newBuilder()
        .hostnameVerifier(
          RecordingHostnameVerifier(),
        ) // Attempt RESTRICTED_TLS then fall back to MODERN_TLS.
        .connectionSpecs(Arrays.asList(ConnectionSpec.RESTRICTED_TLS, ConnectionSpec.MODERN_TLS))
        .sslSocketFactory(
          suppressTlsFallbackClientSocketFactory(),

 *
 * All event methods must execute fast, without external locking, cannot throw exceptions,
 * attempt to mutate the event parameters, or be reentrant back into the client.
 * Any IO - writing to files or network should be done asynchronously.
 */
@ExperimentalOkHttpApi
abstract class ConnectionListener {
  /**
   * Invoked as soon as a call causes a connection to be started.

   *
   * The [dispatcher][OkHttpClient.dispatcher] defines when the request will run: usually
   * immediately unless there are several other requests currently being executed.
   *
   * This client will later call back `responseCallback` with either an HTTP response or a failure
   * exception.
   *
   * @throws IllegalStateException when the call has already been executed.
   */
  fun enqueue(responseCallback: Callback)

Calls are executed in one of two ways:

 * **Synchronous:** your thread blocks until the response is readable.
 * **Asynchronous:** you enqueue the request on any thread, and get [called back](https://square.github.io/okhttp/4.x/okhttp/okhttp3/-callback/) on another thread when the response is readable.

    peer.sendFrame().settings(settings1)
    peer.acceptFrame() // ACK
    peer.sendFrame().ping(false, 2, 0)
    peer.acceptFrame() // PING
    peer.play()

    // Play it back.
    val connection =
      Http2Connection.Builder(true, TaskRunner.INSTANCE)
        .socket(peer.openSocket())
        .pushObserver(Http2ConnectionTest.IGNORE)
        .listener(realConnection)
        .build()

    assertThat(TimeUnit.NANOSECONDS.toMillis(elapsedUntilPong3).toDouble())
      .isCloseTo(1500.0, 250.0)

    // The client pinged the server 3 times, and it has ponged back 3 times.
    assertThat(webSocket.sentPingCount()).isEqualTo(3)
    assertThat(server.receivedPingCount()).isEqualTo(3)
    assertThat(webSocket.receivedPongCount()).isEqualTo(3)

  }

  /**
   * Ignored due to incompatibilities between Android and Java on how non-ASCII subject alt names
   * are parsed. Android fails to parse these, which means we fall back to the CN. The RI does parse
   * them, so the CN is unused.
   */
  @Test fun verifyNonAsciiSubjectAlt() {
    // Expecting actual:
    //  ["bar.com", "花子.co.jp"]
    // to contain exactly (and in same order):

    client.processNextFrame()
    taskFaker.runTasks()
    server.webSocket!!.pong("pong 3".encodeUtf8())
    client.processNextFrame()

    // After 500ms the client automatically pings and the server pongs back.
    taskFaker.advanceUntil(ns(500L))
    server.processNextFrame() // Ping.
    client.processNextFrame() // Pong.

    // After 1000ms the client will attempt a ping 2, but we don't process it. That'll cause the