public static DraweeEventTracker newInstance() {
    return sEnabled ? new DraweeEventTracker() : sInstance;
  }
This class keeps a record of internal events that take place in the Drawee.

<p>Having a record of a last few events is useful for debugging purposes. If you want to disable
it, call {@link DraweeEventTracker#disable()} before {@link Fresco.initialize()}.
drawee/src/main/java/com/facebook/drawee/components/DraweeEventTracker.java