shadows/framework/src/main/java/org/robolectric/shadows/ShadowLegacyChoreographer.java
@Implementation
  protected void postCallback(int callbackType, Runnable action, Object token) {
    postCallbackDelayed(callbackType, action, token, postCallbackDelayMillis);
  }
@Implementation
  protected void postCallback(int callbackType, Runnable action, Object token) {
    postCallbackDelayed(callbackType, action, token, postCallbackDelayMillis);
  }
The default implementation will call {@link #postCallbackDelayed(int, Runnable, Object, long)}
with no delay. {@link android.animation.AnimationHandler} calls this method to schedule
animation updates infinitely. Because during a Robolectric test the system time is paused and
execution of the event loop is invoked for each test instruction, the behavior of
AnimationHandler would result in endless looping (the execution of the task results in a new
animation task created and scheduled to the front of the event loop queue).

<p>To prevent endless looping, a test may call {@link #setPostCallbackDelay(int)} to specify a
small delay when animation is scheduled.

@see #setPostCallbackDelay(int)