[iOS] Introduce TurboModule Setup Metric

[a-dilettante]

Summary

With the introduction of TurboModules, it would be beneficial to measure the setup time of these modules, as we currently have it in place for NativeModules.

The instantiation of the TMs occurs in the RCTTurboModuleManager. In order to successfully measure the time it took to setup the module, we need to ensure that we don't take into account cached modules. As such, we need to:

1. Check if module is in _turboModuleCache
   a. Start mark for RCTPLTurboModuleSetup tag if not found
2. Get the TM via [self provideTurboModule:]
3. Check if module is in _turboModuleCache
   a. Stop mark for RCTPLTurboModuleSetup if we did not find module in cache prior to step 2 and if it's now present in the cache.
   b. Notify about setup time if the above is true.
4. Return TM

Changelog

[iOS] [Added] - Gain insights on the the turbo module setup times by observing RCTDidSetupModuleNotification. The userInfo dictionary will contain the module name and setup time in milliseconds. These values can be extracted via RCTDidSetupModuleNotificationModuleNameKey and RCTDidSetupModuleNotificationSetupTimeKey.

Test Plan

Observe for RCTDidSetupModuleNotification

- (void)setup {
    [_notificationCenter addObserver:self
                            selector:@selector(didSetupModule:)
                                name:RCTDidSetupModuleNotification
                              object:nil];
}

- (void)didSetupModule:(NSNotification *)notification {
    NSDictionary *userInfo = notification.userInfo;
    if (userInfo) {
        NSString *moduleName = userInfo[RCTDidSetupModuleNotificationModuleNameKey];
        NSNumber *setupTime = userInfo[RCTDidSetupModuleNotificationSetupTimeKey];
        NSLog(@"%@ setup took %li ms", moduleName, [setupTime integerValue]);
    }
}

Output

TestTurboModule setup took 1 ms

[shergin]

cc @RSNara

[a-dilettante]

Hello @shergin and @RSNara,

Have you managed to take a look at this PR?

[RSNara]

Whoops. Sorry for the late review!

This looks mostly good, but I'm not convinced that we should split the RCTDidSetupModuleNotification into RCTDidSetupNativeModuleNotification and RCTDidSetupTurboModuleNotification. So, I'm requesting changes to get your input.

[RSNara]

nit: The variable name didFindModuleInCacheBeforeCreation is a bit strange. What you're really checking here is: "Does this TurboModule exist?". So you could just use the moduleIsInitialized function defined further down in the file.

[a-dilettante]

Ahh, perfect - How did I miss that one out? 😅

[RSNara]

Same deal here.

[RSNara]

A module is either a NativeModule or a TurboModule (and you know which is which). So I'm not sure why it's necessary to to break this notification down into two. Eventually, we plan to remove the Bridge and its accompanying NativeModule system, so we'll have to undo this change anyway. Thoughts?

[a-dilettante]

Good shout. It really didn't make sense to do so when I looked at this for the second time.

[a-dilettante]

Hi @RSNara, I've implemented the changes thanks to your feedback and I think we've covered everything.

[RSNara]

Perfect! Thanks 😁

[facebook-github-bot]

@RSNara is landing this pull request. If you are a Facebook employee, you can view this diff on Phabricator.

[react-native-bot]

This pull request was successfully merged by @RCiesielczuk in cd2f8c5.

^{When will my fix make it into a release? | Upcoming Releases}