feat: track network connectivity changes with breadcrumbs

[armcknight]

📜 Description

Monitor reachability of https://sentry.io in SentryBreadcrumbTracker and have its delegate record a breadcrumb every time connectivity changes, recording its description in the breadcrumb data.

Currently calling this breadcrumb type "connectivity", which we'd need to add to https://develop.sentry.dev/sdk/event-payloads/breadcrumbs/#breadcrumb-types. This is subject to change, as is the breadcrumb category of "device.connectivity".

Refactors:

• access SentryReachability via SentryDependencyContainer
• expose description constants eg SentryConnectivityCellular

💡 Motivation and Context

For #3127

💚 How did you test it?

New test case in SentryBreadcrumbTrackerTests.swift.

[github-actions]

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by 🚫 dangerJS against 1c1690e

[codecov]

Codecov Report

Merging #3232 (7fa081e) into main (be2977c) will increase coverage by 0.089%.
Report is 1 commits behind head on main.
The diff coverage is 100.000%.

@@              Coverage Diff              @@
##              main     #3232       +/-   ##
=============================================
+ Coverage   89.128%   89.217%   +0.089%     
=============================================
  Files          502       501        -1     
  Lines        54251     54022      -229     
  Branches     19475     19200      -275     
=============================================
- Hits         48353     48197      -156     
- Misses        4919      4968       +49     
+ Partials       979       857      -122     

Files Changed	Coverage
Sources/Sentry/SentryReachability.m	ø
Sources/Sentry/SentryBreadcrumbTracker.m	100.000%
Sources/Sentry/SentryDependencyContainer.m	100.000%
...ons/Breadcrumbs/SentryBreadcrumbTrackerTests.swift	100.000%
...s/SentryTests/Networking/SentryReachabilityTests.m	100.000%
...entryTests/Networking/TestSentryReachability.swift	100.000%

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[github-actions]

Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	1242.59 ms	1253.88 ms	11.29 ms
Size	22.85 KiB	408.73 KiB	385.88 KiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
881a955	1230.98 ms	1246.22 ms	15.24 ms
3e7aa41	1214.02 ms	1238.84 ms	24.82 ms
98752f3	1240.61 ms	1259.80 ms	19.18 ms
289c0b8	1245.63 ms	1253.76 ms	8.13 ms
b066509	1246.14 ms	1272.42 ms	26.28 ms
fdfe96b	1227.90 ms	1242.56 ms	14.66 ms
dbc67d2	1239.49 ms	1248.88 ms	9.39 ms
4259afd	1222.12 ms	1249.74 ms	27.62 ms
dacf894	1223.96 ms	1250.41 ms	26.45 ms
24b4df1	1240.98 ms	1253.98 ms	13.00 ms

App size

Revision	Plain	With Sentry	Diff
881a955	22.85 KiB	407.63 KiB	384.79 KiB
3e7aa41	20.76 KiB	432.31 KiB	411.55 KiB
98752f3	20.76 KiB	435.09 KiB	414.33 KiB
289c0b8	22.85 KiB	407.67 KiB	384.82 KiB
b066509	22.84 KiB	403.13 KiB	380.29 KiB
fdfe96b	20.76 KiB	419.70 KiB	398.95 KiB
dbc67d2	20.76 KiB	427.74 KiB	406.98 KiB
4259afd	20.76 KiB	419.70 KiB	398.94 KiB
dacf894	20.76 KiB	426.34 KiB	405.58 KiB
24b4df1	20.76 KiB	425.77 KiB	405.01 KiB

Previous results on branch: armcknight/feat/3127-network-change-breadcrumbs

Startup times

Revision	Plain	With Sentry	Diff
41c525b	1218.84 ms	1226.62 ms	7.79 ms
d63a3a5	1257.60 ms	1271.42 ms	13.82 ms
5afbde7	1261.22 ms	1264.67 ms	3.45 ms
a93728b	1240.27 ms	1252.06 ms	11.79 ms
dc541cc	1243.61 ms	1256.54 ms	12.93 ms
6dd4832	1234.71 ms	1256.18 ms	21.47 ms
f94c893	1244.84 ms	1261.40 ms	16.56 ms

App size

Revision	Plain	With Sentry	Diff
41c525b	22.85 KiB	407.46 KiB	384.61 KiB
d63a3a5	22.85 KiB	408.72 KiB	385.88 KiB
5afbde7	22.84 KiB	403.75 KiB	380.90 KiB
a93728b	22.85 KiB	407.75 KiB	384.90 KiB
dc541cc	22.85 KiB	407.88 KiB	385.03 KiB
6dd4832	22.85 KiB	407.92 KiB	385.07 KiB
f94c893	22.85 KiB	407.46 KiB	384.61 KiB

[stefanosiano]

On Android the breadcrumbs have:
type: system
category: network.event
data["action"]: one of NETWORK_AVAILABLE, NETWORK_LOST, NETWORK_CAPABILITIES_CHANGED
Except for the action, i guess we can align on type and category, so they are the same on Android and Cocoa (and flutter and rn as they rely on Android and Cocoa).

We already collect other breadcrumbs under the system type, coming from the system, like temperature, phone state and other generic system events.
I'm updating the meta issue with this info.
I'm not sure if develop docs are to be updated, as these really affect only mobile SDKs, but perhaps it's a good idea anyway, since i didn't find the system type documented anywhere, either.

[armcknight]

Thanks @stefanosiano for the info! Let me know anything I can do to help update docs, even if you just need a review ✨

[armcknight]

I just noticed that much of the relevant implementation of SentryReachability are managed by static state, so instantiating another one and calling -[monitorURL:usingCallback:] will erase the previous monitoring setup by our internal networking stack. This will require more refactoring.

[brustolin]

Code wise looks good, but CI is broken

[brustolin]

LGTM

[armcknight]

@brustolin I pushed a new commit that refactors a couple things:

• allows multiple observers to watch reachability changes
• internalize the URL used to monitor network state
• don't ignore the first reachability callback, as it contains useful information (like, in the happy path, that the network is reachable as of the time monitoring started)
• simplify several flows, including rearranging code in reachability functions to use early exits

[brustolin]

All good with the changes.