Limiters API

TokenBucket / AsyncTokenBucket

TokenBucket(
    capacity: int,              # Max tokens (burst size)
    refill_rate: float,         # Tokens per second
    clock: Clock | None = None,
    ttl: float | None = None,   # Evict buckets after N seconds idle
    max_buckets: int | None = None,  # Max keys (LRU eviction)
    cleanup_interval: int = 100,
)

Method	Description
`allow(key)`	Non-blocking: returns `True` if token consumed
`acquire(key, timeout)`	Block until token available
`get_tokens(key)`	Current token count
`reset(key)`	Reset bucket; `key=None` clears all

Async: use AsyncTokenBucket; allow and acquire are async.

LeakyBucket / AsyncLeakyBucket

LeakyBucket(
    capacity: int,              # Max queue size
    leak_rate: float,           # Requests processed per second
    clock: Clock | None = None,
    ttl: float | None = None,
    max_buckets: int | None = None,
    cleanup_interval: int = 100,
)

Method	Description
`allow(key)`	Non-blocking: returns `True` if queued
`acquire(key, timeout)`	Block until space available
`get_queue_size(key)`	Current queue size
`get_wait_time(key)`	Seconds until space available
`reset(key)`	Clear queue; `key=None` clears all

Async: use AsyncLeakyBucket; allow and acquire are async.