Format:
tick (integer_usec, @func_ref);
Periodically execute a function at specified interval in microseconds. The exact timing of the call is not guaranteed more than the fact the function will be executed after at least the specified number of microseconds have passed. Value 0 in the period will disable further calls to the function.
All parallel processes have independent tick counters, however, only one tick function is possible per process.
Example:
tick 1000000, @myfunc;
The function myfunc() will get executed every 1 second.
An important requirement for tick-handling functions are not to have any input or output parameters.