utils/src/main/java/org/robolectric/util/Scheduler.java
public synchronized void setIdleState(IdleState idleState) {
    this.idleState = idleState;
    switch (idleState) {
      case UNPAUSED:
        advanceBy(0);
        break;
      case CONSTANT_IDLE:
        advanceToLastPostedRunnable();
        break;
      default:
    }
  }
public synchronized void setIdleState(IdleState idleState) {
    this.idleState = idleState;
    switch (idleState) {
      case UNPAUSED:
        advanceBy(0);
        break;
      case CONSTANT_IDLE:
        advanceToLastPostedRunnable();
        break;
      default:
    }
  }
Sets the current idling state of this <tt>Scheduler</tt>. If transitioning to the
{@link IdleState#UNPAUSED} state any tasks scheduled to be run at or before the current time
will be run, and if transitioning to the {@link IdleState#CONSTANT_IDLE} state all scheduled
tasks will be run and the clock advanced to the time of the last runnable.
@param idleState The new idle state of this <tt>Scheduler</tt>.
@see #setIdleState(IdleState)
@see #isPaused()