// WaitWrite waits until data can be written to fd.
func (fd *FD) WaitWrite() error {
	return fd.pd.waitWrite(fd.isFile)
}

// WriteOnce is for testing only. It makes a single write call.
func (fd *FD) WriteOnce(p []byte) (int, error) {
	if err := fd.writeLock(); err != nil {
		return 0, err
	}
	defer fd.writeUnlock()
	return ignoringEINTRIO(syscall.Write, fd.Sysfd, p)
}

	promiseFactoryFactory promiseFactoryFactory
}

// promiseFactory returns a WriteOnce
// - whose Set method is invoked with the queueSet locked, and
// - whose Get method is invoked with the queueSet not locked.
// The parameters are the same as for `promise.NewWriteOnce`.
type promiseFactory func(initial interface{}, doneCtx context.Context, doneVal interface{}) promise.WriteOnce

func countingPromiseFactoryFactory(activeCounter counter.GoRoutineCounter) promiseFactoryFactory {
	return func(qs *queueSet) promiseFactory {
		return func(initial interface{}, doneCtx context.Context, doneVal interface{}) promise.WriteOnce {
			return testpromise.NewCountingWriteOnce(activeCounter, &qs.lock, initial, doneCtx.Done(), doneVal)
		}
	}
}

func TestTotalRequestsExecutingWithPanic(t *testing.T) {
	metrics.Register()