Master timer service for the system.

• Any service wishing to receive a timer message at a fixed interval can register with the TimerService by sending it a "Start" message.
• From that point on, they will get messages with a "Timer" operation every fixed interval.
• If they don't wish to get the timer message, they can send a "Stop" message and they will be removed from future timer messages.
• Currently the timer resolution is 1000 msec
• This is useful if the service wants a timer to process data at specific intervals but doesnt want to setup individual timers which can be expensive and also can have thread synchronization implications for the callbacks.

TODO: clean this docs

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START A NEW TIMER

This makes the timer service send periodic messages to that service.

Operation:

   Defs::Timer::MO_TIMER_START

Arguments:

   [Defs::Timer::MS_TIMER][Defs::Timer::S_TIMER_SERVICE] = ServiceName 
   [Defs::Timer::MS_TIMER][Defs::Timer::S_SERVICE_TAG]   = Service Specified Tag

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STOP AN EXISTING TIMER

This makes the timer service stop sending periodic messages to that service.

Operation:

   Defs::Timer::MO_TIMER_STOP

Arguments:

   [Defs::Timer::MS_TIMER][Defs::Timer::S_TIMER_SERVICE] = ServiceName 
   [Defs::Timer::MS_TIMER][Defs::Timer::S_SERVICE_TAG]   = Service Specified Tag

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TIMER MESSAGE

Operation name indicates this is a timer message.

Operation:

   Defs::Timer::MO_TIMER

Arguments:

   [Defs::Timer::MS_TIMER][Defs::Timer::S_TIMER_TAG] = Service Specific Tag