完善服务器

Server/common/proto/grpc/gateway.proto

@@ -4,6 +4,11 @@ option go_package = "common/proto/gen/grpc_pb";
 import "common.proto";
 
 service Gateway {
-  rpc SendMessage(Empty) returns (Empty) {}
+  rpc ToClient(stream ToClientReq) returns (Empty) {}
+}
+
+message ToClientReq {
+  int32 UID = 1;
+  bytes Payload = 2;
 }