src/main/java/org/jboss/util/collection/ConcurrentSkipListMap.java
final boolean unlink(Index<K,V> succ) {
            return !indexesDeletedNode() && casRight(succ, succ.right);
        }
final boolean unlink(Index<K,V> succ) {
            return !indexesDeletedNode() && casRight(succ, succ.right);
        }
Tries to CAS right field to skip over apparent successor
succ.  Fails (forcing a retraversal by caller) if this node
is known to be deleted.
@param succ the expected current successor
@return true if successful