Wait for GRPC channel ready. (#43)
Wait for GRPC channel ready. (#43)

* Wait for GRPC channel ready.

* Allow break waiting GRPC channel ready.
bytedance/fedlearner,bytedance/fedlearner,bytedance/fedlearner,bytedance/fedlearner,bytedance/fedlearner,bytedance/fedlearner,bytedance/fedlearner