input

type Semaphore interface {
	// Acquire acquires the semaphore with a weight of n, blocking until
	// resources are available or ctx is done. On success, returns nil. On
	// failure, returns ctx.Err() and leaves the semaphore unchanged.
	Acquire(context.Context, int64) error
	// TryAcquire acquires the semaphore with a weight of n without blocking. On
	// success, returns true. On failure, returns false and leaves the semaphore
	// unchanged.
	TryAcquire(int64) bool
	// Release releases the semaphore with a weight of n.
	Release(int64)
}