private void startFlushHandlerThreads(FlushHandler[] flushHandlers, int start, int end) {
    if (flusherThreadFactory != null) {
      for (int i = start; i < end; i++) {
        flushHandlers[i] = new FlushHandler("MemStoreFlusher." + flusherIdGen.getAndIncrement());
        flusherThreadFactory.newThread(flushHandlers[i]);
        flushHandlers[i].start();
      }
    }
  }
@param when When to expire, when to come up out of the queue. Specify in milliseconds. This
            method adds EnvironmentEdgeManager.currentTime() to whatever you pass.
@return This.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreFlusher.java