// this private API to avoid having to change the type of ForkLock.
// For more details see the syscall package.
//
//go:linkname syscall_hasWaitingReaders syscall.hasWaitingReaders
func syscall_hasWaitingReaders(rw *RWMutex) bool {
	r := rw.readerCount.Load()
	return r < 0 && r+rwmutexMaxReaders > 0
}

// RLocker returns a [Locker] interface that implements