Copas Timer is a module that adds a timer capability to the
Copas scheduler. It provides the same base functions step and
loop as Copas (it actually replaces them) except that it will
also check for (and run) timers expiring and run background
workers if there is no IO or timer to handle. It also adds
methods to allow for a controlled exit from the loop.
As an optional component an 'eventer' is available to dispatch
events as background tasks in Copas Timer.
- fixed undefined behaviour when arming an already armed timer