src/main/java/org/organicdesign/fp/tuple/Tuple2.java
public static <K,V> Tuple2<K,V> of(Map.Entry<K,V> entry) {
        // Protect against multiple-instantiation
        if (entry instanceof Tuple2) {
            return (Tuple2<K,V>) entry;
        }
        return new Tuple2<>(entry.getKey(), entry.getValue());
    }
public static <K,V> Tuple2<K,V> of(Map.Entry<K,V> entry) {
        // Protect against multiple-instantiation
        if (entry instanceof Tuple2) {
            return (Tuple2<K,V>) entry;
        }
        return new Tuple2<>(entry.getKey(), entry.getValue());
    }
Map.Entry factory method