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.
If the remote handler is blocked on a send, and the client is trying to send without the remote receiving, 
the operation would become deadlocked if the channels are full.

### Typed handlers

		if next == nil {
			break // No more waiters blocked.
		}

		w := next.Value.(waiter)
		if s.size-s.cur < w.n {
			// Not enough tokens for the next waiter.  We could keep going (to try to
			// find a waiter with a smaller request), but under load that could cause
			// starvation for large requests; instead, we leave all remaining waiters
			// blocked.
			//

	}()

	select {
	case <-done:
		t.Fatalf("%s unexpectedly did not block", desc)
		return nil

	case <-time.After(quiescent):
		t.Logf("%s is blocked (as expected)", desc)
		return func(t *testing.T) {
			t.Helper()
			select {
			case <-time.After(probablyStillBlocked):
				t.Fatalf("%s is unexpectedly still blocked", desc)
			case <-done:
			}
		}
	}
}

	// a bit baroque to remove a signal stack here only to add one
	// in minit, but it's a simple change that keeps NetBSD
	// working like other OS's. At this point all signals are
	// blocked, so there is no race.
	memset(&ss, 0, sizeof ss);
	ss.ss_flags = SS_DISABLE;
	sigaltstack(&ss, nil);

	crosscall1(ts.fn, setg_gcc, ts.g);
	return nil;

     */
    WaitPrecondition getWaitPrecondition();

    /**
     * Releases any blocked requests, in preparation for shutdown.
     */
    void cancelBlockedRequests();

    /**
     * Asserts that this handler has been completed successfully.
     */

		r.mu.Unlock()
		return 0, err
	}
	var (
		counter uint64
		block   [aes.BlockSize]byte
	)
	inc := func() {
		counter++
		if counter == 0 {
			panic("crypto/rand counter wrapped")
		}
		byteorder.LePutUint64(block[:], counter)
	}
	blockCipher.Encrypt(r.key[:aes.BlockSize], block[:])
	inc()
	blockCipher.Encrypt(r.key[aes.BlockSize:], block[:])
	inc()
	r.mu.Unlock()

	n = len(b)

// relation at all.
//
// [the Go memory model]: https://go.dev/ref/mem
type Mutex struct {
	state int32
	sema  uint32
}

// A Locker represents an object that can be locked and unlocked.
type Locker interface {
	Lock()
	Unlock()
}

const (
	mutexLocked = 1 << iota // mutex is locked
	mutexWoken
	mutexStarving
	mutexWaiterShift = iota

	// Mutex fairness.
	//

	return r < 0 && r+rwmutexMaxReaders > 0
}

// RLocker returns a [Locker] interface that implements
// the [RWMutex.Lock] and [RWMutex.Unlock] methods by calling rw.RLock and rw.RUnlock.
func (rw *RWMutex) RLocker() Locker {
	return (*rlocker)(rw)
}

type rlocker RWMutex

func (r *rlocker) Lock()   { (*RWMutex)(r).RLock() }

func runtime_SemacquireRWMutexR(s *uint32, lifo bool, skipframes int)
func runtime_SemacquireRWMutex(s *uint32, lifo bool, skipframes int)

// Semrelease atomically increments *s and notifies a waiting goroutine
// if one is blocked in Semacquire.
// It is intended as a simple wakeup primitive for use by the synchronization
// library and should not be used directly.
// If handoff is true, pass count directly to the first waiter.

			return
		}
		locked <- struct{}{}
		if blerr = bl.Close(); blerr != nil {
			t.Error(blerr)
			return
		}
	}()

	select {
	case <-locked:
		t.Error("unexpected unblocking")
	case <-time.After(100 * time.Millisecond):
	}

	// unlock
	if err = dupl.Close(); err != nil {
		t.Fatal(err)
	}

	// the previously blocked routine should be unblocked
	select {
	case <-locked: