refactor.

lichao

2021-06-02 ab898268c8bc493ca9862b2d64f2e1e7d20e5a4c

 src/exported_symbols

@@ -5,6 +5,7 @@
   BHUnregister;
   BHRegisterTopics;
   BHQueryTopicAddress;
   BHQueryProcs;
   BHSubscribeTopics;
   BHStartWorker;
   BHHeartbeatEasy;