shadows/framework/src/main/java/org/robolectric/shadows/ShadowMessage.java
@Resetter
  public static void reset() {
    Object lock = reflector(ReflectorMessage.class).getPoolSync();
    synchronized (lock) {
      reflector(ReflectorMessage.class).setPoolSize(0);
      reflector(ReflectorMessage.class).setPool(null);
    }
  }
@Resetter
  public static void reset() {
    Object lock = reflector(ReflectorMessage.class).getPoolSync();
    synchronized (lock) {
      reflector(ReflectorMessage.class).setPoolSize(0);
      reflector(ReflectorMessage.class).setPool(null);
    }
  }
Resets the static state of the {@link Message} class by
emptying the message pool.