public Set<Map.Entry<K, V>> getEntrySet() {
        if (mEntrySet == null) {
            mEntrySet = new EntrySet();
        }
        return mEntrySet;
    }
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