semaphore

Supports acquire and release with custom weights, enabling fine-grained resource control for scenarios like rate limiting with variable costs, as shown in the usage examples.

Integrates with Go's context package for cancellable and timeout-based acquisitions, making it robust for real-world concurrent applications with deadlines or cancellations.

Allows resizing the semaphore limit after creation via SetLimit, providing flexibility without reinitialization, a feature highlighted in the README.

Offers TryAcquire for immediate, non-blocking permit attempts, useful for responsive systems where blocking is undesirable.

Built using compare-and-swap operations, with benchmarks showing it outperforms many channel-based semaphores, especially under load with lower latency.