Implementation of a task manager that allows tracking
and managing asynchronous tasks.
The tasks are represented by task_manager::task class providing
members common to all types of tasks. The methods that differ
among tasks of different module can be overriden in a class
inheriting from task_manager::task::impl class. Each task stores
its status containing parameters like id, sequence number, begin
and end time, state etc. After the task finishes, it is kept
in memory for configurable time or until it is unregistered.
Tasks need to be created with make_task method.
Each module is represented by task_manager::module type and should
have an access to task manager through task_manager::module methods.
That allows to easily separate and collectively manage data
belonging to each module.
2439e55974