How to detect gRPC connection loss as soon as possible in v. 2.0?

[Vladlex]

Hello, I'd like to discuss the best approach (or any) for detecting channel disconnection (offline) as quickly as possible.

Context:
We have an iOS app that should show connection indicator (like "idle/offline", "connecting", "connected").

What are you trying to achieve?

I look for an interface which allows me to observe state of connection or connection pool.

What have you tried so far?

I can see a very similiar question here, but is't related for a v1.0 version.
I've looked into grpc-swift source code and can see, that's ClientConnection is exist, but it has package level access.

[glbrntt]

At the moment there's no API exposed for doing this. If you wanted this info you could add an application layer check which, for example, pings the server every few seconds. That would at least tell you whether there is a connection.

Internally we do keep track of this as an async sequence of connectivity states and I wouldn't be opposed to exposing something like it. We may need to change the current semantics a little. I suspect the desired behaviour here would be to take the current connectivity state when the async sequence is first consumed and ignore any earlier states. It may also be helpful to support multiple consumers.