@Override
        public void run() {
          if (!running) {
            return;
          }
          if (LOG.isTraceEnabled()) {
            LOG.trace("running");
          }
          try {
            closeIdle(false);
          } finally {
            // explicitly reschedule so next execution occurs relative
            // to the end of this scan, not the beginning
            scheduleIdleScanTask();
          }
        }
The number of open RPC conections
@return the number of open rpc connections
hbase-server/src/main/java/org/apache/hadoop/hbase/ipc/SimpleRpcServer.java