import core.thread : Thread;

StopWatch sw;
sw.setTimeElapsed(hours(1));

// As discussed in MonoTime's documentation, converting between
// Duration and ticks is not exact, though it will be close.
// How exact it is depends on the frequency/resolution of the
// system's monotonic clock.
assert(abs(sw.peek() - hours(1)) < usecs(1));

sw.start();
Thread.sleep(usecs(1));
assert(sw.peek() > hours(1) + usecs(1));