protected boolean isEqualKey(Object key1, Object key2) {
        return (key1 == key2);
    }
Compares two keys for equals.
This implementation uses <code>==</code>.

@param key1 the first key to compare
@param key2 the second key to compare
@return true if equal by identity
jphp-runtime/src/php/runtime/common/collections/map/IdentityMap.java