utils/src/main/java/org/robolectric/util/Scheduler.java
public synchronized boolean runOneTask() {
    ScheduledRunnable postedRunnable = runnables.poll();
    if (postedRunnable != null) {
      if (postedRunnable.scheduledTime > currentTime) {
        currentTime = postedRunnable.scheduledTime;
      }
      postedRunnable.run();
      return true;
    }
    return false;
  }
public synchronized boolean runOneTask() {
    ScheduledRunnable postedRunnable = runnables.poll();
    if (postedRunnable != null) {
      if (postedRunnable.scheduledTime > currentTime) {
        currentTime = postedRunnable.scheduledTime;
      }
      postedRunnable.run();
      return true;
    }
    return false;
  }
Run the next runnable in the queue.

@return  True if a runnable was executed.