client.send(message2)
    serverListener.assertTextMessage(message2)

    // Empty server to client message.
    val message3 = ""
    server.send(message3)
    clientListener.assertTextMessage(message3)

    // Empty client to server message.
    val message4 = ""
    client.send(message4)
    serverListener.assertTextMessage(message4)

    client.processNextFrame() // Read server close, send client close, close connection.
    assertThat(client.closed).isFalse()
    client.listener.assertClosing(1000, "Hello!")
    client.webSocket!!.finishReader()
    client.webSocket!!.close(1000, "Hello!")
    server.processNextFrame()
    server.listener.assertClosing(1000, "Hello!")
    server.webSocket!!.finishReader()
    client.listener.assertClosed(1000, "Hello!")

   * `promisedStreamId` to which response frames will be delivered. Push promise frames are sent as
   * a part of the response to `streamId`. The `promisedStreamId` has a priority of one greater than
   * `streamId`.
   *
   * @param streamId client-initiated stream ID.  Must be an odd number.
   * @param promisedStreamId server-initiated stream ID.  Must be an even number.

 * to mutate the event parameters, or be re-entrant back into the client. Any IO - writing to files
 * or network should be done asynchronously.
 */
abstract class EventListener {
  /**
   * Invoked as soon as a call is enqueued or executed by a client. In case of thread or stream
   * limits, this call may be executed well before processing the request is able to begin.
   *

  private val source: BufferedSource,
  private val client: Boolean,
) : Closeable {
  private val continuation: ContinuationSource = ContinuationSource(this.source)
  private val hpackReader: Hpack.Reader =
    Hpack.Reader(
      source = continuation,
      headerTableSizeSetting = 4096,
    )

  @Throws(IOException::class)
  fun readConnectionPreface(handler: Handler) {
    if (client) {

    protected static final String AZUREAD_TENANT = "aad.tenant";

    /** Configuration key for Azure AD client secret. */
    protected static final String AZUREAD_CLIENT_SECRET = "aad.client.secret";

    /** Configuration key for Azure AD client ID. */
    protected static final String AZUREAD_CLIENT_ID = "aad.client.id";

    /** Configuration key for Azure AD reply URL. */

with OkHttp 3.x: must use `object :` with OkHttp 4.x:

Kotlin calling OkHttp 3.x:

```kotlin
val client = OkHttpClient.Builder()
    .dns { hostname -> InetAddress.getAllByName(hostname).toList() }
    .build()
```

Kotlin calling OkHttp 4.x:

```kotlin
val client = OkHttpClient.Builder()
    .dns(object : Dns {
      override fun lookup(hostname: String) =

    checkState(count() > 1);
    return sumOfProductsOfDeltas / (count() - 1);
  }

  /**
   * Returns the <a href="http://mathworld.wolfram.com/CorrelationCoefficient.html">Pearson's or
   * product-moment correlation coefficient</a> of the values. The count must greater than one, and
   * the {@code x} and {@code y} values must both have non-zero population variance (i.e. {@code

    val requestLine = "CONNECT ${url.toHostHeader(includeDefaultPort = true)} HTTP/1.1"
    while (true) {
      val tunnelCodec =
        Http1ExchangeCodec(
          // No client for CONNECT tunnels:
          client = null,
          carrier = this,
          socket = socket,
        )
      socket.source.timeout().timeout(readTimeoutMillis.toLong(), TimeUnit.MILLISECONDS)

          throw ProtocolException("Received HTTP_PROXY_AUTH (407) code while not using proxy")
        }
        return client.proxyAuthenticator.authenticate(route, userResponse)
      }

      HTTP_UNAUTHORIZED -> return client.authenticator.authenticate(route, userResponse)

      HTTP_PERM_REDIRECT, HTTP_TEMP_REDIRECT, HTTP_MULT_CHOICE, HTTP_MOVED_PERM, HTTP_MOVED_TEMP, HTTP_SEE_OTHER -> {