Swarm Event Intuition

[AgeManning]

Description

I have been recently doing some debugging.

My assumptions where that the SwarmEvents would be general, in the sense that they would catch all errors. So matching on these would give a good overview of the system.

I've noticed in particular, that the SwarmEvent::OutgoingConnectionError does not include ConnectionDenied events. So if dialing a peer fails, it is not registered in the SwarmEvents, rather I have to match on a behviour event, particularly FromSwarm::DialFailure (https://github.com/libp2p/rust-libp2p/blob/master/swarm/src/behaviour.rs#L425)

I think mostly these two events show the same information, but the SwarmEvent one is less general. I would have assumed the swarm event to be more general than the behaviour event.

I am just pointing this out because in case this is not intended.

[thomaseizinger]

Once we fix #3046 (which is basically already done, we are just delaying merging breaking changes at the moment), we can - as a follow-up - express SwarmEvent as a composition of FromSwarm and NetworkBehaviour::ToSwarm which should resolve these inconsistencies once and for all!

[thomaseizinger]

I am closing this in favor of #4268.