utils/src/main/java/org/robolectric/util/Scheduler.java
public synchronized boolean advanceBy(long amount, TimeUnit unit) {
    long endingTime = currentTime + unit.toMillis(amount);
    return advanceTo(endingTime);
  }
public synchronized boolean advanceBy(long amount, TimeUnit unit) {
    long endingTime = currentTime + unit.toMillis(amount);
    return advanceTo(endingTime);
  }
Run all runnables that are scheduled to run in the next time interval.

@return  True if a runnable was executed.