NewNoValueQueue wraps a handler that only returns an error to create a [Queue] that produces [NoValue] for each key.

NewQueue creates a [Queue] with the provided concurrency limit and handler.

KeyMutex provides mutual exclusion among operations targeting a given comparable key.

NoValue is the canonical empty value type for a [Queue].

Queue is a concurrency-limited deduplicating work queue.

QueueHandle allows a [Handler] to interact with its parent queue.

Stats conveys information about the keys and results in a [Queue].

Handler is the type for a [Queue]'s handler function.