@Override
  public synchronized void start() {
    super.start();
    if (!isStarted && !isEmbedded) {
      initServer();
      serverThread = new Thread(this);
      serverThread.setName("Thrift Server");
      serverThread.start();
      isStarted = true;
    }
  }
Return the number of Hive sessions this context has handled. It is
technically possible that a single connection context could handle an
unbounded number of sequential Hive sessions, though it is currently not
implemented.

@return The number of sessions this thrift context has handled
service/src/java/org/apache/hive/service/cli/thrift/ThriftCLIService.java