This module implements the sidejob_worker logic used by all worker processes created to manage a sidejob resource. This code emulates the gen_server API, wrapping a provided user-specified module which implements the gen_server behavior.

The primary purpose of this module is updating the usage information published in a given resource's ETS table, such that capacity limiting operates correctly. The sidejob_worker also cooperates with a given sidejob_resource_stats server to maintain statistics about a given resource.

By default, a sidejob_worker calculates resource usage based on message queue size. However, the user-specified module can also choose to implement the current_usage/1 and rate/1 callbacks to change how usage is calculated. An example is the sidejob_supervisor module which reports usage as: queue size + num_children.