NewScheduleWorker creates a new task scheduling worker.

NewTaskWorker creates a new Task Worker instance, the worker will enforce a default heartbeat ttl of 15 seconds.

NewTaskWorkerWithOpts creates a task Worker instance with the specified options.

ErrHeartbeatTimeout is returned from the worker when the task heartbeat is too slow, tasks must heartbeat every 15s or else the worker abandons he task.

ErrScheduleQueueIsEmpty occurs when there is no schedule with the `next_execution_time` in the past.

Options controls how the worker behaves.