Report reason for shutdown in collection.rs

[tomaka]

When a connection starts its shutdown phase, we now report why.
This is at the moment only reported by the API of collection.rs, and we need #2370 in order to propagate it further.

[mergify]

Automatically approving tomaka's pull requests. This auto-approval will be removed once more maintainers are active.

[github-actions]

twiggy diff report

Difference in .wasm size before and after this pull request.

---

 Delta Bytes │ Item
─────────────┼────────────────────────────────────────────────────────────────────────────────────────────
       +3638 ┊ smoldot::libp2p::collection::Network<TConn,TNow>::next_event::hf765bac886403693
       -3602 ┊ smoldot::libp2p::collection::Network<TConn,TNow>::next_event::h68df47466f700250
        -241 ┊ <smoldot::libp2p::collection::RequestError as core::clone::Clone>::clone::h30c3e32cddae463b
        +241 ┊ <smoldot::libp2p::collection::RequestError as core::clone::Clone>::clone::h61c24b04b739da7e
        -225 ┊ alloc::collections::vec_deque::ring_slices::RingSlices::ring_slices::h014e653fe69bc4c2
        +225 ┊ alloc::collections::vec_deque::ring_slices::RingSlices::ring_slices::h1cad2d3fbfc36a72
        +225 ┊ alloc::collections::vec_deque::ring_slices::RingSlices::ring_slices::ha366ee058002abc1
        -225 ┊ alloc::collections::vec_deque::ring_slices::RingSlices::ring_slices::hedb564612c10e597
        +202 ┊ alloc::raw_vec::RawVec<T,A>::grow_exact::h2ae08296266d2735
        -202 ┊ alloc::raw_vec::RawVec<T,A>::grow_exact::h64736d42396aed2d
        +202 ┊ alloc::raw_vec::RawVec<T,A>::grow_exact::ha4fa756fa17baece
        -202 ┊ alloc::raw_vec::RawVec<T,A>::grow_exact::hc43c9bca3fb1bacc
        +190 ┊ alloc::collections::vec_deque::VecDeque<T,A>::grow::h9f24b5f191d38eb3
        -190 ┊ alloc::collections::vec_deque::VecDeque<T,A>::grow::ha443f8a99941045c
        -190 ┊ alloc::collections::vec_deque::VecDeque<T,A>::grow::hbbe5cce25f2c0364
        +190 ┊ alloc::collections::vec_deque::VecDeque<T,A>::grow::hfec808c1cb12358c
        -181 ┊ alloc::raw_vec::RawVec<T,A>::allocate_in::h105339d8a9c80936
        -181 ┊ alloc::raw_vec::RawVec<T,A>::allocate_in::h1237c7d322b926e6
        +181 ┊ alloc::raw_vec::RawVec<T,A>::allocate_in::hb90dee381cad2372
        +181 ┊ alloc::raw_vec::RawVec<T,A>::allocate_in::hbcdc89653607308f
        +173 ┊ ... and 65 more.
        +209 ┊ Σ [85 Total Rows]

[melekes]

👍