A global timer facility

A small library which provides a global timer facility in Elixir (or Erlang). There are two callable functions:

• timer_ref = Gtimer.new_timer(timeout,timeout_action \\ nil). Starts a new timer running for timeout millseconds, returns a "timer reference".
• Gtimer.cancel_timer(timer_ref). Cancels a running timer.

If a running timer is not cancelled when the timer expires the timeout_action function will be called with the process identifier pidof the process that created the timer as a single argument. If the timeout_action is not a function of arity 1, then the default action of terminating the process pid, and displaying an informative message, will be taken.

Timer management is done in a separate (GenServer) process which will be linked to the process executing the new_timer call. Inside the process timers are stored in a priority queue, and using a map, which affords logarithmic worst-case time complexity for both function calls (in terms of the number of timers running).

An example:

timer_ref = Gtimer.new_timer(1000,fn pid -> Process.exit(pid,:because) end)

This will start a new timer which when it expires kills the process which invoked the call to new_timer.