public long elapsed(TimeUnit desiredUnit) {
        return desiredUnit.convert(elapsedNanos(), NANOSECONDS);
    }
Returns the current elapsed time shown on this stopwatch, expressed
in the desired time unit, with any fraction rounded down.

<p>Note that the overhead of measurement can be more than a microsecond, so
it is generally not useful to specify {@link TimeUnit#NANOSECONDS}
precision here.

@since 14.0 (since 10.0 as {@code elapsedTime()})
lts-core/src/main/java/com/github/ltsopensource/core/commons/concurrent/limiter/Stopwatch.java