race in `main` in torrent announce

```
==================
WARNING: DATA RACE
Write at 0x00c00a68caa8 by goroutine 725358:
github.com/anacrolix/torrent/tracker/udp.(*Client).request()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/tracker/udp/client.go:236 +0x834
github.com/anacrolix/torrent/tracker/udp.(*Client).Announce()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/tracker/udp/client.go:40 +0x357
github.com/anacrolix/torrent/tracker/udp.(*ConnClient).Announce()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/tracker/udp/conn-client.go:129 +0x10c
github.com/anacrolix/torrent/tracker.(*udpClient).Announce()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/tracker/udp.go:44 +0x164
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).singleAnnounce()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:635 +0x5f9
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).singleAnnounceAttempter()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:617 +0x3ef
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).startAnnounce.gowrap1()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:532 +0x8a

Previous write at 0x00c00a68caa8 by goroutine 725361:
github.com/anacrolix/torrent/tracker/udp.(*Client).request()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/tracker/udp/client.go:236 +0x834
github.com/anacrolix/torrent/tracker/udp.(*Client).Announce()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/tracker/udp/client.go:40 +0x357
github.com/anacrolix/torrent/tracker/udp.(*ConnClient).Announce()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/tracker/udp/conn-client.go:129 +0x10c
github.com/anacrolix/torrent/tracker.(*udpClient).Announce()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/tracker/udp.go:44 +0x164
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).singleAnnounce()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:635 +0x5f9
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).singleAnnounceAttempter()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:617 +0x3ef
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).startAnnounce.gowrap1()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:532 +0x8a

Goroutine 725358 (running) created at:
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).startAnnounce()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:532 +0x39b
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).dispatchAnnounces()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:508 +0x75
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).step()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:437 +0x149
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).timerFunc()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:418 +0x92
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).timerFunc-fm()
:1 +0x2e
github.com/anacrolix/torrent/internal/mytimer.(*Timer).innerCallback()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/internal/mytimer/my-timer.go:69 +0xd2
github.com/anacrolix/torrent/internal/mytimer.(*Timer).innerCallback-fm()
:1 +0x2e

Goroutine 725361 (running) created at:
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).startAnnounce()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:532 +0x39b
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).dispatchAnnounces()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:508 +0x75
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).step()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:437 +0x149
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).timerFunc()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/client-tracker-announcer.go:418 +0x92
github.com/anacrolix/torrent.(*regularTrackerAnnounceDispatcher).timerFunc-fm()
:1 +0x2e
github.com/anacrolix/torrent/internal/mytimer.(*Timer).innerCallback()
/home/erigon/go/pkg/mod/github.com/anacrolix/torrent@v1.61.1-0.20260306043331-7dea980541ac/internal/mytimer/my-timer.go:69 +0xd2
github.com/anacrolix/torrent/internal/mytimer.(*Timer).innerCallback-fm()
:1 +0x2e
==================
```