Calls can be canceled from any thread. This will fail the call if it hasn’t yet completed! Code that is writing the request body or reading the response body will suffer an `IOException` when its call is canceled.

## Dispatch

      @Override
      @SuppressWarnings("Interruption") // We are propagating an interrupt from a caller.
      public void cancel(boolean mayInterruptIfRunning) {
        /*
         * Lock to ensure that a task cannot be rescheduled while a cancel is ongoing.
         *
         * In theory, cancel() could execute arbitrary listeners -- bad to do while holding a lock.

    }

    @Override
    public boolean isCancelled() {
      return sync.isCancelled();
    }

    @CanIgnoreReturnValue
    @Override
    public boolean cancel(boolean mayInterruptIfRunning) {
      if (!sync.cancel(mayInterruptIfRunning)) {
        return false;
      }
      executionList.execute();
      if (mayInterruptIfRunning) {
        interruptTask();
      }
      return true;

	// current accumulated status of the heal sequence
	currentStatus healSequenceStatus

	// channel signaled by background routine when traversal has
	// completed
	traverseAndHealDoneCh chan error

	// canceler to cancel heal sequence.
	cancelCtx context.CancelFunc

	// the last result index sent to client
	lastSentResultIndex int64

	// Number of total items scanned against item type

  }

  public void testListenerCalledOnCancelFromRunning() throws Exception {
    exec.execute(task);
    runLatch.await();

    // Task has started up, cancel it while it's running.
    task.cancel(true);
    assertTrue(task.isDone());
    assertTrue(task.isCancelled());
    assertEquals(1, taskLatch.getCount());

    // Wait for the listeners to be called.

  object : BufferedSocket {
    private val delegate = this@asBufferedSocket
    override val source = delegate.source.buffer()
    override val sink = delegate.sink.buffer()

    override fun cancel() {
      delegate.cancel()
    }

   *
   * <p>If {@code future} succeeds, its value will be closed (using {@code closingExecutor)}) when
   * the pipeline is done, even if the pipeline is canceled or fails.
   *
   * <p>Cancelling the pipeline will not cancel {@code future}, so that the pipeline can access its
   * value in order to close it.
   *
   * @param future the future to create the {@code ClosingFuture} from. For discussion of the

          : getUninterruptibly(future, timeoutDuration, timeoutUnit);
    } catch (InterruptedException e) {
      future.cancel(true);
      throw e;
    } catch (ExecutionException e) {
      throw throwCause(e, true /* combineStackTraces */);
    } catch (TimeoutException e) {
      future.cancel(true);
      throw new UncheckedTimeoutException(e);
    }
  }

  @CanIgnoreReturnValue
  @Override

    // stop it.
    blockingCallable.waitForStart();

    // This time, cancel the future for the first task. The task remains running, only the future
    // is cancelled.
    future1.cancel(false);

    // Give the second task a chance to (incorrectly) start up while the first task is running.
    // (This is the assertion that fails.)

	u.RawQuery = q.Encode()
	return u.String(), nil
}

// Put - Adds DNS entries into operator webhook server
func (c *OperatorDNS) Put(bucket string) error {
	ctx, cancel := context.WithTimeout(context.Background(), defaultOperatorContextTimeout)
	defer cancel()
	e, err := c.endpoint(bucket, false)
	if err != nil {
		return newError(bucket, err)
	}
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, e, nil)