offer(e); // never need to block
  }

  @CanIgnoreReturnValue // pushed down from class to method
  @Override
  public @Nullable E poll() {
    Monitor monitor = this.monitor;
    monitor.enter();
    try {
      return q.poll();
    } finally {
      monitor.leave();
    }
  }

  @CanIgnoreReturnValue // pushed down from class to method
  @Override

            blocks:
              - type: "section"
                text:
                  type: "mrkdwn",

 * connections should expect repetition of stream IDs.
 *
 * Return true to request cancellation of a pushed stream.  Note that this does not guarantee
 * future frames won't arrive on the stream ID.
 */
interface PushObserver {
  /**
   * Describes the request that the server intends to push a response for.
   *
   * @param streamId server-initiated stream ID: an even number.

- [ ] Check ["Allow edit from maintainers" option](https://help.github.com/articles/allowing-changes-to-a-pull-request-branch-created-from-a-fork/) in pull request so that additional changes can be pushed by Gradle team.
- [ ] Provide integration tests (under `<subproject>/src/integTest`) to verify changes from a user perspective.
- [ ] Provide unit tests (under `<subproject>/src/test`) to verify logic.

    /**
     * Whether the <a href="https://www.jetbrains.com/help/teamcity/configuring-vcs-triggers.html">VCS trigger</a>
     * should be enabled, i.e. when new commits are pushed to this branch, should a ReadyForNightly job
     * be triggered automatically?
     *
     * Currently, we only enable VCS trigger for `master`/`release`/`releaseNx` branches.
     */

### Threads

#### Application's calling thread

The application-layer must block on writing I/O. We can't return from a write until we've pushed its bytes onto the socket. Otherwise, if the write fails we are unable to deliver its IOException to the application. We would have told the application layer that the write succeeded, but it didn't!

     * pushed stream to this response.
     */
    public fun addPush(promise: PushPromise): Builder =
      apply {
        this.pushPromises_ += promise
      }

    /**
     * When [protocols][MockWebServer.protocols] include [HTTP_2][okhttp3.Protocol], this pushes
     * [settings] before writing the response.
     */

  private val writerQueue = taskRunner.newQueue()

  /** Ensures push promise callbacks events are sent in order per stream. */
  private val pushQueue = taskRunner.newQueue()

  /** Notifies the listener of settings changes. */
  private val settingsListenerQueue = taskRunner.newQueue()

  /** User code to run in response to push promise events. */
  private val pushObserver: PushObserver = builder.pushObserver

    *   A new environment variable `TF_XLA_DEBUG_OPTIONS_PASSTHROUGH` set to "1"
        or "true" allows the debug options passed within an XRTCompile op to be
        passed directly to the XLA compilation backend. If such variable is not
        set (service side), only a restricted set will be passed through.
    *   Allow the XRTCompile op to return the ProgramShape resulted form the XLA
        compilation as a second return argument.

* Add a new feature gate for enabling an alpha annotation which,...