// number of goroutines holding a conceptual write lock
	// on ForkLock.
	forking int
)

// hasWaitingReaders reports whether any goroutine is waiting
// to acquire a read lock on rw. It is defined in the sync package.
func hasWaitingReaders(rw *sync.RWMutex) bool

// acquireForkLock acquires a write lock on ForkLock.
// ForkLock is exported and we've promised that during a fork

// 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