req := updateRequest{
		Update: data,
		Fd:     fd,
		Resp:   ret,
	}
	select {
	case z.Updates <- req:
	case <-ctx.Done():
		return nil, fmt.Errorf("context expired before request sent: %v", ctx.Err())
	}

	select {
	case r := <-ret:
		return r.resp, r.err
	case <-ctx.Done():
		return nil, fmt.Errorf("context expired before response received: %v", ctx.Err())
	}
}

func (es *expiryState) enqueueTierJournalEntry(je jentry) {
	wrkr := es.getWorkerCh(je.OpHash())
	if wrkr == nil {
		es.stats.missedTierJournalTasks.Add(1)
		return
	}
	select {
	case <-GlobalContext.Done():
	case wrkr <- je:
	default:
		es.stats.missedTierJournalTasks.Add(1)
	}
}

// enqueueFreeVersion enqueues a free version to be deleted
func (es *expiryState) enqueueFreeVersion(oi ObjectInfo) {

It is designed to have functions that receive two parameters, one "request" and one "response". Then you "read" parts from the request, and "write" parts to the response. Because of this design, it is not possible to declare request parameters and bodies with standard Python type hints as function parameters.

				xfer := make([]expireObjInfo, len(toDel))
				copy(xfer, toDel)

				var done bool
				select {
				case <-ctx.Done():
					done = true
				case expireCh <- xfer:
					toDel = toDel[:0] // resetting toDel
				}
				if done {
					break
				}
			}
			var match BatchJobExpireFilter
			var found bool
			for _, rule := range r.Rules {

// at least one member of verbs matches the request, (b) at least one
// member of apiGroups matches the request, (c) at least one member of
// resources matches the request, and (d) either (d1) the request does
// not specify a namespace (i.e., `Namespace==""`) and clusterScope is
// true or (d2) the request specifies a namespace and least one member
// of namespaces matches the request's namespace.

		wg.Add(1)
		go func(ctx context.Context, peerChannel <-chan MetricV2, wg *sync.WaitGroup) {
			defer wg.Done()
			for {
				select {
				case m, ok := <-peerChannel:
					if !ok {
						return
					}
					select {
					case ch <- m:
					case <-ctx.Done():
						return
					}
				case <-ctx.Done():
					return
				}
			}
		}(ctx, peerChannels[index], &wg)
	}

	timer := time.NewTimer(globalAPIConfig.getDeleteCleanupInterval())
	defer timer.Stop()

	for {
		select {
		case <-ctx.Done():
			return
		case <-timer.C:
			var wg sync.WaitGroup
			for _, set := range s.sets {
				wg.Add(1)
				go func(set *erasureObjects) {
					defer wg.Done()
					if set == nil {
						return
					}
					set.cleanupDeletedObjects(ctx)
				}(set)
			}
			wg.Wait()

   *
   * <p>Duplicate elements are considered equal. For example, the list [1, 1] will have only one
   * permutation, instead of two. This is why the elements have to implement {@link Comparable}.
   *
   * <p>An empty iterable has only one permutation, which is an empty list.
   *
   * <p>This method is equivalent to {@code Collections2.orderedPermutations(list,
   * Ordering.natural())}.

	wg.Add(1)

	// Start the callback in a new green thread so that if we later fail
	// to switch the namespace back to the original one, we can safely
	// leave the thread locked to die without a risk of the current thread
	// left lingering with incorrect namespace.
	var innerError error
	go func() {
		defer wg.Done()
		runtime.LockOSThread()
		innerError = containedCall()
	}()
	wg.Wait()

	return innerError

	return &adminErasureTestBed{
		erasureDirs: erasureDirs,
		objLayer:    objLayer,
		router:      adminRouter,
		done:        cancel,
	}, nil
}

// TearDown - method that resets the test bed for subsequent unit
// tests to start afresh.
func (atb *adminErasureTestBed) TearDown() {
	atb.done()
	removeRoots(atb.erasureDirs)
	resetTestGlobals()
}