Java 8 TimeIt combo

TimeIt.java

import static java.lang.System.nanoTime;

/*
 * Usage:
 *   final long then = TimeIt.start();
 *   ...
 *   final long elapsed = TimeIt.elapsedSince(then);
 *   recorder.record(elapsed);
 */
public class TimeIt {
    public static long start() { return nanoTime(); }

    public static long elapsedSince(long then) {
        final long now = nanoTime();
        return now - then;
    }
    
    public static Runnable timed(Runnable runnable, LongConsumer recorder) {
        final long then = start();
        runnable.run();
        recorder.record(elapsedSince(then));
    }
};