Provides core support for scheduling and interacting with background activity.

## Package Specification

This package specifies API for scheduling background tasks, or jobs. Jobs can be scheduled for immediate execution, or for execution after a specified delay. Once scheduled, jobs can be queried, canceled, or suspended. Rules can be attached to jobs to indicate when they can run, and whether they can run simultaneously with other jobs. This package also includes a generic locking facility that includes support for detecting and responding to deadlock.

@since 3.0