feat: add basic tracing

[guseggert]

No description provided.

[Jorropo]

This generate outputs like this:

[guillaumemichel]

Any reasons not to add a context as argument to Refresh?

go-libp2p-kad-dht/rtrefresh/rt_refresh_manager.go

Lines 103 to 121 in 471e058

	// RefreshRoutingTable requests the refresh manager to refresh the Routing Table.
	// If the force parameter is set to true true, all buckets will be refreshed irrespective of when they were last refreshed.
	//
	// The returned channel will block until the refresh finishes, then yield the
	// error and close. The channel is buffered and safe to ignore.
	func (r *RtRefreshManager) Refresh(force bool) <-chan error {
	resp := make(chan error, 1)
	r.refcount.Add(1)
	go func() {
	defer r.refcount.Done()
	select {
	case r.triggerRefresh <- &triggerRefreshReq{respCh: resp, forceCplRefresh: force}:
	case <-r.ctx.Done():
	resp <- r.ctx.Err()
	}
	}()
	return resp
	}

[Jorropo]

Any reasons not to add a context as argument to Refresh ?

@guillaumemichel thx for the review <3

Refresh merge concurrent calls into one single refresh (if a refresh is in flight and you try to refresh once more, nothing happens and you return once the already in flight refresh finishes).

If we start accepting contextes we will have to do a dance of keeping a tally of how many calls still want the refresh, because a cancel of one of them shouldn't cancel the full refresh if other peoples are relying on it.

I could add a context here but it would make the code more complex for what seems a small benefit over using r.ctx.

[guillaumemichel]

LGTM! I am OK with merging, we can always add more spans later if needed.