* {@code null}!) before returning it to callers. Depending on how the code is structured, a
   * nullness analysis might not understand that the field has been populated. To avoid that problem
   * without having to add {@code @SuppressWarnings}, the code can call this method.
   *
   * <p>Why <i>not</i> just add {@code SuppressWarnings}? The problem is that this method is

      /*
       * requireNonNull is safe because we don't null out `sequencer` except:
       *
       * - after the requireNonNull call below. (And this object has its Runnable.run override
       *   called only once, just as it has its Executor.execute override called only once.)
       *
       * - if we return immediately from `execute` (in which case we never get here)
       *

        .header("Sec-WebSocket-Version", "13")
        .header("Sec-WebSocket-Extensions", "permessage-deflate")
        .build()
    call = RealCall(webSocketClient, request, forWebSocket = true)
    call!!.enqueue(
      object : Callback {
        override fun onResponse(
          call: Call,
          response: Response,
        ) {
          val exchange = response.exchange
          val streams: Streams
          try {

  }

  /**
   * Wrapper for {@link Map#get(Object)} that forces the caller to pass in a key of the same type as
   * the map. Besides being slightly shorter than code that uses {@link #getMap()}, it also ensures
   * that callers don't pass an {@link Entry} by mistake.
   */
  protected V get(K key) {
    return getMap().get(key);
  }

   * the {@code Future} is already done. Second, if buggy code calls {@code getDone} on a {@code
   * Future} that is still pending, the program will throw instead of block. This can be important
   * for APIs like {@link #whenAllComplete whenAllComplete(...)}{@code .}{@link
   * FutureCombiner#call(Callable, Executor) call(...)}, where it is easy to use a new input from
   * the {@code call} implementation but forget to add it to the arguments of {@code

  // scheduled on that same threadpool, causing a deadlock in cases where the
  // caller of event_mgr->ThenExecute() blocks on the completion of the callback
  // (as in the case of ConstOp kernel creation on GPU, which involves copying a
  // CPU tensor to GPU).
  // Setting a larger thread pool does not help with the Swift caller, as we use
  // a different TFE context for each thread of execution (for running graph

      /*
       * requireNonNull is safe because we don't null out `sequencer` except:
       *
       * - after the requireNonNull call below. (And this object has its Runnable.run override
       *   called only once, just as it has its Executor.execute override called only once.)
       *
       * - if we return immediately from `execute` (in which case we never get here)
       *

  val b0 = this[index].code
  val b1 = this[index + 1].code
  return (b0 shl 7) + b1
}

/**
 * An extremely generic binary search that doesn't know what data it's searching over. The caller
 * provides indexes and a comparison function, and this calls that function iteratively.
 *
 * @return the index of the match. If no match is found this is `(-1 - insertionPoint)`, where the

   *     different kind of exception, that exception itself. To avoid hiding bugs and other
   *     unrecoverable errors, callers should prefer more specific types, avoiding {@code
   *     Throwable.class} in particular.
   * @param fallback the {@link Function} to be called if the input fails with the expected
   *     exception type. The function's argument is the input's exception. "The input's exception"

   */
  abstract class Listener {
    /**
     * Called when the service transitions from {@linkplain State#NEW NEW} to {@linkplain
     * State#STARTING STARTING}. This occurs when {@link Service#startAsync} is called the first
     * time.
     */
    public void starting() {}

    /**
     * Called when the service transitions from {@linkplain State#STARTING STARTING} to {@linkplain