private void updateHeadKey(long destroyedKey) throws CacheException {
    headKey = inc(destroyedKey);
    if (logger.isTraceEnabled()) {
      logger.trace("{}: Incremented HEAD_KEY for region {} to {}", this, region.getName(),
          headKey);
    }
  }
Increments the value of the head key by one.
geode-core/src/main/java/org/apache/geode/internal/cache/wan/serial/SerialGatewaySenderQueue.java