Utility class that measures the elapsed time
SF::Clock is a lightweight class for measuring time.
Its provides the most precise time that the underlying OS can achieve (generally microseconds or nanoseconds). It also ensures monotonicity, which means that the returned time can never go backward, even if the system time is changed.
clock = SF::Clock.new ... time1 = clock.elapsed_time ... time2 = clock.restart()
SF::Time value returned by the clock can then be
converted to a number of seconds, milliseconds or even
Returns a shallow copy of this object.
This allocates a new object and copies the contents of
self into it.
Get the elapsed time
Returns: Time elapsed