| AdHash | 
 This incremental hash is used to keep track of the hash of
 the data tree to that we can quickly validate that things
 are in sync. 
 | 
| AuthUtil | 
  | 
| BitHashSet | 
 Using BitSet to store all the elements, and use HashSet to cache limited
 number of elements to find a balance between memory and time complexity. 
 | 
| BitMap<T> | 
 This is a helper class to maintain the bit to specific value and the
 reversed value to bit mapping. 
 | 
| CircularBuffer<T> | 
 Thread safe FIFO CircularBuffer implementation. 
 | 
| ConfigUtils | 
  | 
| JvmPauseMonitor | 
 This code is originally from hadoop-common, see:
 https://github.com/apache/hadoop/blob/trunk/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/util/JvmPauseMonitor.java
 Class which sets up a simple thread which runs in a loop sleeping
 for a short interval of time. 
 | 
| KerberosUtil | 
  | 
| LogChopper | 
 this class will chop the log at the specified zxid 
 | 
| MessageTracker | 
 This class provides a way of buffering sentBuffer and receivedBuffer messages in order. 
 | 
| OSMXBean | 
 This class is a wrapper for the implementation of
 com.sun.management.UnixOperatingSystemMXBean
 It will decide to use the sun api or its own implementation
 depending on the runtime (vendor) used. 
 | 
| QuotaMetricsUtils | 
  | 
| RateLimiter | 
 A class that provides simple interval-based rate limiting implementation. 
 | 
| RequestPathMetricsCollector | 
 This class holds the requests path ( up till a certain depth) stats per request type 
 | 
| SerializeUtils | 
  | 
| VerifyingFileFactory | 
  | 
| VerifyingFileFactory.Builder | 
  | 
| ZxidUtils | 
  |