workqueue

type Interface[T comparable] interface {
	// Add marks an item as needing processing. If the item is not already
	// in the dirty set, it is added to the queue. If the item is currently
	// being processed, it is added to the dirty set so it will be re-queued
	// when Done is called.
	Add(item T)

	// Len returns the current number of items in the queue.
	Len() int

	// Get blocks until an item is available, then returns it along with a
	// shutdown indicator. If shutdown is true, the caller should exit.
	// The caller MUST call Done with the item when processing is complete.
	Get() (item T, shutdown bool)

	// Done marks an item as finished processing. If the item was re-added
	// (dirty) while being processed, it is re-enqueued.
	// This MUST be called for every item returned by Get.
	Done(item T)

	// ShutDown signals the queue to shut down. All blocked Get calls will
	// return with shutdown=true. Further Add calls are ignored.
	ShutDown()

	// ShutDownWithDrain signals shutdown but continues to process existing
	// items until the queue is empty. New items added after this call are
	// accepted only if the queue hasn't fully drained yet.
	ShutDownWithDrain()

	// ShuttingDown returns true if ShutDown or ShutDownWithDrain has been called.
	ShuttingDown() bool
}