* transform(ing) data in 512-bit message block(s), updating the variables
     * context and count, and leaving (buffering) the remaining bytes in buffer
     * for the next update or finish.
     *
     * @param    input    input block
     * @param    offset    start of meaningful bytes in input
     * @param    len        count of bytes in input block to consider
     */

  // Requests that the worker thread execute the specified operation. Blocks
  // until the previously pending operation (a StartExecute without a Join) has
  // finished, if any.
  //
  // `cancellation_manager` must live until after `Join` finishes and pending
  // `is_async` operations finish. In addition to allowing the caller to cancel
  // the operation, its `StartCancel` method will be called if op execution

        grid.PutByteBuffer(result)
        return nil
    })
```

Context cancellation and timeouts are propagated to the handler. 
The client does not wait for the remote handler to finish before returning.
Returning any error will also cancel the stream remotely.

CAREFUL: When utilizing two-way communication, it is important to ensure that the remote handler is not blocked on a send.

	srcSha256 := sha256.New()
	tgtSha256 := sha256.New()

	for {
		srcSha256.Reset()
		tgtSha256.Reset()

		srcEOF = !srcOk
		tgtEOF = !tgtOk

		// No objects from source AND target: Finish
		if srcEOF && tgtEOF {
			break
		}

		if !srcEOF && srcCtnt.Err != nil {
			log.Fatal(srcCtnt.Err)
		}

		if !tgtEOF && tgtCtnt.Err != nil {
			log.Fatal(tgtCtnt.Err)
		}

	// stop the replay go-routine.
	if h.store != nil {
		h.storeCtxCancel()
	}

	// Set logch to nil and close it.
	// This will block all Send operations,
	// and finish the existing ones.
	// All future ones will be discarded.
	h.logChMu.Lock()
	xioutil.SafeClose(h.logCh)
	h.logCh = nil
	h.logChMu.Unlock()

	if h.producer != nil {
		h.producer.Close()

	// time-duration to keep heal sequence state after it
	// completes.
	keepHealSeqStateDuration = time.Minute * 10

	// nopHeal is a no operating healing action to
	// wait for the current healing operation to finish
	nopHeal = ""
)

var (
	errHealIdleTimeout   = errors.New("healing results were not consumed for too long")
	errHealStopSignalled = errors.New("heal stop signaled")

  @Override
  public void setUp() {
    threadPool = newCachedThreadPool();
  }

  @Override
  public void tearDown() throws InterruptedException {
    threadPool.shutdown();
    assertTrue("Some worker didn't finish in time", threadPool.awaitTermination(10, SECONDS));
  }

  private static <T> int drain(
      BlockingQueue<T> q,
      Collection<? super T> buffer,
      int maxElements,
      long timeout,

	if f.testWG != nil {
		defer f.testWG.Done()
	}
	args := f.Called(ambientPods)
	return args.Error(0)
}

// Custom "wait group with timeout" for waiting for fakeServer calls in a goroutine to finish
type WaitGroup struct {
	count int32
	done  chan struct{}
}

func NewWaitGroup() *WaitGroup {
	return &WaitGroup{
		done: make(chan struct{}),
	}
}

    a2.cancel()
    a3.cancel()
    assertThat(dispatcher.runningCalls())
      .containsExactlyInAnyOrder(a1, a2)
    assertThat(dispatcher.queuedCalls()).isEmpty()

    // Let the calls finish.
    waiting.countDown()
    t1.join()
    t2.join()

    // Now we should have 0 running calls and 0 queued calls.
    assertThat(dispatcher.runningCallsCount()).isEqualTo(0)

   * missRate =~ 1.0}. Cache misses include all requests which weren't cache hits, including
   * requests which resulted in either successful or failed loading attempts, and requests which
   * waited for other threads to finish loading. It is thus the case that {@code missCount >=
   * loadSuccessCount + loadExceptionCount}. Multiple concurrent misses for the same key will result
   * in a single load operation.
   */
  public double missRate() {