private int hashOf(Object key) {
        return hash(identityComparisons ?
                System.identityHashCode(key) : key.hashCode());
    }
Returns the segment that should be used for key with given hash
@param hash the hash code for the key
@return the segment
commons-profiler/src/main/java/com/navercorp/pinpoint/common/profiler/concurrent/jsr166/ConcurrentReferenceHashMap.java