Well, there is `EngineCon` interface [1]. And two types (`engineIPC` [2] and `engineRPC` [3]) that implement the interface. That's why there is some repetition. So, what?

[1]: https://github.com/google/seesaw/blob/master/common/conn/con... [2]: https://github.com/google/seesaw/blob/master/common/conn/ipc... [3]: https://github.com/google/seesaw/blob/master/common/conn/rpc...