root, cancel := WithCancel(Background())
	m := map[Context]CancelFunc{root: cancel}
	q := []Context{root}
	// Create a tree of contexts.
	for len(q) != 0 && len(m) < 100 {
		parent := q[0]
		q = q[1:]
		for i := 0; i < 4; i++ {
			ctx, cancel := WithCancel(parent)
			m[ctx] = cancel
			q = append(q, ctx)
		}
	}
	// Start all the cancels in a random order.
	var wg sync.WaitGroup

	return contextName(c.Context) + ".WithCancel"
}

// cancel closes c.done, cancels each of c's children, and, if
// removeFromParent is true, removes c from its parent's children.
// cancel sets c.cause to cause if this is the first time c is canceled.
func (c *cancelCtx) cancel(removeFromParent bool, err, cause error) {
	if err == nil {
		panic("context: internal error: missing cancel error")
	}
	if cause == nil {
		cause = err
	}

using ops::QueueDequeue;
using ops::QueueEnqueue;
using ops::RandomNormal;
using ops::Square;
using ops::Variable;

constexpr char kAssignOpName[] = "assign";
constexpr char kCancelOp0[] = "cancel0";
constexpr char kCancelOp1[] = "cancel1";
constexpr char kCloseOp0[] = "close0";
constexpr char kCloseOp1[] = "close1";
constexpr char kCountUpToOpName[] = "count";
constexpr char kDequeueOp0[] = "dequeue0";

	}
	initialReqCancel := req.Cancel // the user's original Request.Cancel, if any

	var cancelCtx func()
	if timeBeforeContextDeadline(deadline, oldCtx) {
		req.ctx, cancelCtx = context.WithDeadline(oldCtx, deadline)
	}

	cancel := make(chan struct{})
	req.Cancel = cancel

	doCancel := func() {
		// The second way in the func comment above:
		close(cancel)
		// The first way, used only for RoundTripper

	if err != nil {
		atomic.AddInt64(&h.failedMessages, 1)
		return
	}
	// Delete the event from store.
	return h.store.Del(key.Name)
}

// Cancel - cancels the target
func (h *Target) Cancel() {
	// If queuestore is configured, cancel it's context to
	// stop the replay go-routine.
	if h.store != nil {
		h.storeCtxCancel()
	}

	// Set logch to nil and close it.

	if err != nil {
		return nil, cancel, "", err
	}
	applyHeaders(req.Header, header, "Accept",
		"User-Agent",
		"X-Prometheus-Scrape-Timeout-Seconds",
	)

	resp, err := s.http.Do(req)
	if err != nil {
		return nil, cancel, "", fmt.Errorf("error scraping %s: %v", url, err)
	}
	if resp.StatusCode != http.StatusOK {
		resp.Body.Close()

	c.mutex.Lock()
	defer c.mutex.Unlock()

	if active := c.activePlugins[driverName]; active != nil {
		active.cancel(errors.New("plugin has re-registered"))
	}
	active := &activePlugin{}
	cancelCtx, cancel := context.WithCancelCause(c.ctx)
	active.cancel = cancel
	c.activePlugins[driverName] = active
	c.queue.Add(driverName)

	c.wg.Add(1)
	go func() {
		defer c.wg.Done()

	ctx, cancel := context.WithCancel(context.Background())
	cancel()
	return ctx, cancel
}
func deadlinedContext() (context.Context, context.CancelFunc) {
	ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond)
	for ctx.Err() != context.DeadlineExceeded {
		time.Sleep(501 * time.Microsecond)
	}
	return ctx, cancel
}

		atomic.AddInt64(&h.failedMessages, 1)
		return errors.New("log buffer full")
	}

	return nil
}

// Cancel - cancels the target.
// All queued messages are flushed and the function returns afterwards.
// All messages sent to the target after this function has been called will be dropped.
func (h *Target) Cancel() {
	atomic.StoreInt32(&h.status, statusClosed)
	h.storeCtxCancel()

	// Wait for messages to be sent...

    inFinished: Boolean,
  ) {
    pushQueue.execute("$connectionName[$streamId] onHeaders") {
      val cancel = pushObserver.onHeaders(streamId, requestHeaders, inFinished)
      ignoreIoExceptions {
        if (cancel) writer.rstStream(streamId, ErrorCode.CANCEL)
        if (cancel || inFinished) {
          this.withLock {
            currentPushRequests.remove(streamId)
          }
        }
      }