public static int getHashKey(EntryOperation event) {
    return getHashKey(event, null, null, null, null, null);
  }
Runs hashCode() on given key/routing object producing a long value and then finds absolute
value of the modulus with bucketSize. For better key distribution, possibly use MD5 or SHA or
any unique ID generator for the hash function.

@param event entry event created for this entry operation
@return the bucket id the key/routing object hashes to
geode-core/src/main/java/org/apache/geode/internal/cache/PartitionedRegionHelper.java