For ENG-6333, first version of latency watchdog.
For ENG-6333, use java thread instead of voltDB scheduleWork thread,
insert latency inspection points in network threads and ExecutionEngine
thread.
For ENG-6333, 2nd version of latency watchdog.
For ENG-6333, add logging rate limiter in latency watchdog.
For ENG-6333, change latency spike monitor points to see if latency
watchdog works.
For ENG-6333, add more latency spike inspection points.
For ENG-6333, replace System.out.println with VoltLogger.
For ENG-6333, run() method of latency watchdog should be sychronized.
For ENG-6333, use ConcurrentHashMap instead of HashMap.
For ENG-6333, use linked hash map to record timestamp per thread.
For ENG-6333, remove debug code.
For ENG-6333, add license header and method description.
For ENG-6333, use ConcurrentHashMap to record timestamp per thread,
start watchdog thread by reading system property.
For ENG-6333, remove WatchdogTimestamp, use AtomicLong to record
timestamp, lazySet timestamp if there is old timestamp value. Add
latency spike watch points.
For ENG-6333, minor refactor to remove isEnabled method, rely on inlining instead, use thread local to get at the value, log using HOST logger at info level
Merge pull request #1378 from VoltDB/ENG-6333-latency-logging

Eng 6333 latency logging