feature request: make native network connectivity validation optional

[bam80]

In some circumstances, as proxy chaining, it's a priory known the native network connectivity would fail.
mtg doctor "Validate native network connectivity" check may take up to a minute just because of that:

$ mtg doctor /config/config.toml 
...
# slowdown here..
Validate native network connectivity
  ❌ DC 1: dial tcp [2001:b28:f23d:f001::a]:443: i/o timeout
  ❌ DC 2: dial tcp [2001:67c:4e8:f002::a]:443: i/o timeout
  ❌ DC 3: dial tcp [2001:b28:f23d:f003::a]:443: i/o timeout
  ❌ DC 4: dial tcp [2001:67c:4e8:f004::a]:443: i/o timeout
  ❌ DC 5: dial tcp [2001:b28:f23f:f005::a]:443: i/o timeout
  ❌ DC 203: dial tcp [2a0a:f280:203:a:5000::100]:443: i/o timeout

# .. and then quick again
Validate network connectivity with proxy
  ✅ DC 1
  ✅ DC 2
  ✅ DC 3
  ✅ DC 4
  ✅ DC 5
  ✅ DC 203

Could we make the native network connectivity validation optional please?

cc @dolonet

[dolonet]

Took a closer look — confirmed in internal/cli/doctor.go: checkNetwork (~:219) loops 6 DCs sequentially, each with a 10s context.WithTimeout (:277). So worst-case is the ~60s observed.

Sent #485, which runs the per-DC dials concurrently (output ordering preserved). Cuts the worst case from ~60s to a single ~10s window, regardless of whether network.proxies is configured.

@bam80 — does this address the slowness sufficiently for you, or is the goal really to suppress the section's output entirely? If the latter, happy to send a separate flag PR.

[bam80]

I think both async and the option would be fine - do not want to wait even 10 seconds.
Thanks.

PS: the use case doesn't look as much marginal to me - why else would you want proxies if you have the connection?

[dolonet]

Fair point on the PS — if network.proxies is set, the native dialer isn't the path to Telegram by design, so a timeout there isn't really an edge case.

Sent #488 — re-sends the --skip-native-check flag (same diff as the closed #484; the original branch was already deleted, so it's a fresh PR rather than a reopen). Independent of #485, lands in either order:

• doctor: run DC connectivity probes in parallel #485 (parallel dials): unconditional speedup for everyone, ~60s → ~10s worst case.
• doctor: add --skip-native-check flag #488 (--skip-native-check): zero-wait path when you know native egress isn't expected to work.