internal var nextStreamId = if (builder.client) 3 else 2

  private var isShutdown = false

  /** For scheduling everything asynchronous. */
  private val taskRunner = builder.taskRunner

  /** Asynchronously writes frames to the outgoing socket. */
  private val writerQueue = taskRunner.newQueue()

  /** Ensures push promise callbacks events are sent in order per stream. */

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.

   dropped in 2.0.

## Version 1.5.4

_2014-04-14_

 * Drop ALPN support in Android. There's a concurrency bug in all
   currently-shipping versions.
 * Support asynchronous disconnects by breaking the socket only. This should
   prevent flakiness from multiple threads concurrently accessing a stream.

## Version 1.5.3

_2014-03-29_

 *
 * ```java
 * Call call = client.newCall(request);
 * try (Response response = call.execute()) {
 * ... // Use the response.
 * }
 * ```
 *
 * You can use a similar block for asynchronous calls:
 *
 * ```java
 * Call call = client.newCall(request);
 * call.enqueue(new Callback() {
 *   public void onResponse(Call call, Response response) throws IOException {

    releases of OkHttp are not compatible with OkHttp 3.5. When upgrading to the new package
    please note that the `WebSocket` and `WebSocketCall` classes have been merged. Sending messages
    is now asynchronous and they may be enqueued before the web socket is connected.

 *  **OkHttp no longer attempts a direct connection if the system's HTTP proxy fails.** This

_2014-05-23_

OkHttp 2 is designed around a new API that is true to HTTP, with classes for
requests, responses, headers, and calls. It uses modern Java patterns like
immutability and chained builders. The API now offers asynchronous callbacks
in addition to synchronous blocking calls.

#### API Changes

 *  **New Request and Response types,** each with their own builder. There's also

      this.routeDatabase = okHttpClient.routeDatabase
      this.taskRunner = okHttpClient.taskRunner
    }

    /**
     * Sets the dispatcher used to set policy and execute asynchronous requests. Must not be null.
     */
    fun dispatcher(dispatcher: Dispatcher) =
      apply {
        this.dispatcher = dispatcher
      }

    /**

  val directory: Path,
  private val appVersion: Int,
  internal val valueCount: Int,
  /** Returns the maximum number of bytes that this cache should use to store its data. */
  maxSize: Long,
  /** Used for asynchronous journal rebuilds. */
  taskRunner: TaskRunner,
) : Closeable, Flushable {
  internal val fileSystem: FileSystem =
    object : ForwardingFileSystem(fileSystem) {
      override fun sink(
        file: Path,

  /** Returns the trailers after the HTTP response. May be empty. */
  @Throws(IOException::class)
  fun trailers(): Headers

  /**
   * Cancel this stream. Resources held by this stream will be cleaned up, though not synchronously.
   * That may happen later by the connection pool thread.
   */
  fun cancel()

  /**
   * Carries an exchange. This is usually a connection, but it could also be a connect plan for

   */
  fun cancel()

  fun interface Factory {
    /**
     * Creates a new web socket and immediately returns it. Creating a web socket initiates an
     * asynchronous process to connect the socket. Once that succeeds or fails, `listener` will be
     * notified. The caller must either close or cancel the returned web socket when it is no longer
     * in use.
     */