ISPN-4424 Synchronize updating cache entry and making a copy
ISPN-4424 Synchronize updating cache entry and making a copy
- making the CacheEntry immutable is not enough, the whole CacheEntry hierarchy needs to be made immutable
- using clone is simpler that making the hierarchy immutable
ISPN-3729 Minimize the number of moved segments for SyncConsistentHashFactory

Based on the original consistent hashing paper, the
NewSyncConsistentHashFactory algorithm doesn't move any segments at all.