Method asyncComplete

test/cpp/src/TestServer.cpp:397–399

    communicate("postWrite", ctx, fn_name);
  }
  void asyncComplete(void* ctx, const char* fn_name) override {
    communicate("asyncComplete", ctx, fn_name);
  }
  void handlerError(void* ctx, const char* fn_name) override {
    communicate("handlerError", ctx, fn_name);
  }