code: @HiddenApi
    @Implementation(minSdk = LOLLIPOP)
    public void recycleUnchecked() {
      if (getApiLevel() >= LOLLIPOP) {
        unschedule();
        directlyOn(realMessage, Message.class, "recycleUnchecked");
      } else {
        // provide forward compatibility with SDK 21.
        recycle();
      }
    }
docs: Hook to unscheduled the callback when the message is recycled.
  Invokes {@link #unschedule()} and then calls through to the
  package private method {@link Message#recycleUnchecked()}
  on the real object.