@Override
        public Map.Entry<K, V> next() {
            if (!hasNext()) throw new NoSuchElementException();
            mIndex++;
            mEntryValid = true;
            return this;
        }
Helper for writing standard Java collection interfaces to a data
structure like {@link ArrayMap}.
android/android_framework/base/src/main/java/github/tornaco/android/thanos/core/util/collection/MapCollections.java