@Override
        public int hashCode() {
            if (!mEntryValid) {
                throw new IllegalStateException(
                        "This container does not support retaining Map.Entry objects");
            }
            final Object key = colGetEntry(mIndex, 0);
            final Object value = colGetEntry(mIndex, 1);
            return (key == null ? 0 : key.hashCode()) ^
                    (value == null ? 0 : value.hashCode());
        }
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