public synchronized ArrayList<C> copyCallbacks() {
        ArrayList<C> callbacks = new ArrayList<C>(mCallbacks.size());
        int numListeners = mCallbacks.size();
        for (int i = 0; i < numListeners; i++) {
            if (!isRemoved(i)) {
                callbacks.add(mCallbacks.get(i));
            }
        }
        return callbacks;
    }
Makes a copy of the registered callbacks and returns it.

@return a copy of the registered callbacks.
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/util/obs/CallbackRegistry.java