Modify the throttle setting
a Future that completes once at least throttle_ns nanoseconds have expired since the last task AND task completes
Set the throttle setting
the throttle period in nanoseconds
A trait that ensures a series of tasks run no faster than the throttle setting. Callers schedule tasks by calling the run method. If at least throttle setting nanoseconds have passed since the last task completed, the supplied function is immediately executed, otherwise it is scheduled for execution once throttle nanoseconds have expired. Tasks scheduled at the same time for later execution will be executed in a FIFO manner. Throttler guarantees that all tasks will have at least throttle nanoseconds separating their completion. However, it can not guarantee that the elapsed time between tasks will not be greater than the throttle setting.