core/muxing: Flatten StreamMuxer interface to `poll_{inbound,outbou…

…nd,address_change,close}` (libp2p#2724)

Instead of having a mix of `poll_event`, `poll_outbound` and `poll_close`, we
flatten the entire interface of `StreamMuxer` into 4 individual functions:

- `poll_inbound`
- `poll_outbound`
- `poll_address_change`
- `poll_close`

This design is closer to the design of other async traits like `AsyncRead` and
`AsyncWrite`. It also allows us to delete the `StreamMuxerEvent`.

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 - Update to `libp2p-request-response` `v0.20.0`.
 
+- Update to `libp2p-core` `v0.35.0`.
+
 # 0.5.0
 
 - Update to `libp2p-core` `v0.34.0`.

Cargo.toml

@@ -18,7 +18,7 @@ async-trait = "0.1"
 futures = "0.3"
 futures-timer = "3.0"
 instant = "0.1"
-libp2p-core = { version = "0.34.0", path = "../../core", default-features = false }
+libp2p-core = { version = "0.35.0", path = "../../core", default-features = false }
 libp2p-swarm = { version = "0.38.0", path = "../../swarm" }
 libp2p-request-response = { version = "0.20.0", path = "../request-response" }
 log = "0.4"