*
   * <p>Cancellation does not propagate from the output future to a callable that has begun to
   * execute, but if the output future is cancelled before {@link Callable#call()} is invoked,
   * {@link Callable#call()} will not be invoked.
   */
  public <T extends @Nullable Object> ListenableFuture<T> submit(
      Callable<T> callable, Executor executor) {
    checkNotNull(callable);

  static final String MULTIPLE_EDGES_CONNECTING =
      "Cannot call edgeConnecting() when parallel edges exist between %s and %s. Consider calling "
          + "edgesConnecting() instead.";
  static final String PARALLEL_EDGES_NOT_ALLOWED =
      "Nodes %s and %s are already connected by a different edge. To construct a graph "
          + "that allows parallel edges, call allowsParallelEdges(true) on the Builder.";

_2019-09-29_

 *  Fix: Cancel calls that fail due to unexpected exceptions. We had a bug where an enqueued call
    would never call back if it crashed with an unchecked throwable, such as a
    `NullPointerException` or `OutOfMemoryError`. We now call `Callback.onFailure()` with an
    `IOException` that reports the call as canceled. The triggering exception is still delivered to
    the thread's `UncaughtExceptionHandler`.

        // Do something with payload
        return []byte("response"), nil
    }

    err := manager.RegisterSingleHandler(grid.HandlerDiskInfo, handler)
```

Sample call:
```go
    // Get a connection to the remote host
    conn := manager.Connection(host)

    payload := []byte("request")
    response, err := conn.SingleRequest(ctx, grid.HandlerDiskInfo, payload)
```

   * value. Otherwise, a call that passes one {@code loader} may return the result of another call
   * with a differently behaving {@code loader}. For example, a call that requests a short timeout
   * for an RPC may wait for a similar call that requests a long timeout, or a call by an
   * unprivileged user may return a resource accessible only to a privileged user making a similar

        // When & Then
        assertTrue(negotiationRequest.isSigningEnforced(), "First call should return true");
        assertFalse(negotiationRequest.isSigningEnforced(), "Second call should return false");
        assertTrue(negotiationRequest.isSigningEnforced(), "Third call should return true");

        verify(negotiationRequest, times(3)).isSigningEnforced();
    }

    @Test

	public fun requestBodyStart (Lokhttp3/Call;)V
	public fun requestFailed (Lokhttp3/Call;Ljava/io/IOException;)V
	public fun requestHeadersEnd (Lokhttp3/Call;Lokhttp3/Request;)V
	public fun requestHeadersStart (Lokhttp3/Call;)V
	public fun responseBodyEnd (Lokhttp3/Call;J)V
	public fun responseBodyStart (Lokhttp3/Call;)V
	public fun responseFailed (Lokhttp3/Call;Ljava/io/IOException;)V

   *
   * @return {@code true} if the network was modified as a result of this call
   */
  @CanIgnoreReturnValue
  boolean removeNode(N node);

  /**
   * Removes {@code edge} from this network, if it is present.
   *
   * @return {@code true} if the network was modified as a result of this call
   */
  @CanIgnoreReturnValue
  boolean removeEdge(E edge);

        final Call call = client.newCall(request);

        // Schedule a job to cancel the call in 1 second.
        executor.schedule(new Runnable() {
          @Override public void run() {
            System.out.printf("%.2f Canceling call.%n", (System.nanoTime() - startNanos) / 1e9f);
            call.cancel();
            System.out.printf("%.2f Canceled call.%n", (System.nanoTime() - startNanos) / 1e9f);

    val call = client.newCall(request)
    val response =
      Response
        .Builder()
        .request(request)
        .code(200)
        .message("")
        .protocol(Protocol.HTTP_2)
        .build()
    val listener = loggingEventListenerFactory.create(call)
    listener.cacheConditionalHit(call, response)
    listener.cacheHit(call, response)
    listener.cacheMiss(call)