Fix issue with sync manifest downloading

[serhii-londar]

Closes #169

[codecov]

Codecov Report

Merging #174 (3335a6a) into master (e4fa76e) will increase coverage by 0.71%.
The diff coverage is 77.50%.

@@            Coverage Diff             @@
##           master     #174      +/-   ##
==========================================
+ Coverage   55.94%   56.64%   +0.71%     
==========================================
  Files         118      119       +1     
  Lines        4019     4151     +132     
==========================================
+ Hits         2248     2351     +103     
- Misses       1771     1800      +29     

Impacted Files	Coverage Δ
...rs/Crowdin/Extensions/CrowdinSDK+ReactNative.swift	0.00% <0.00%> (ø)
...n/MappingDownloader/CrowdinMappingDownloader.swift	0.00% <0.00%> (ø)
...wdin/MappingDownloader/CrowdinMappingManager.swift	0.00% <0.00%> (ø)
...ders/Crowdin/ManifestManager/ManifestManager.swift	79.27% <78.21%> (-20.73%)	⬇️
...ers/Crowdin/CrowdinRemoteLocalizationStorage.swift	72.23% <79.17%> (+5.56%)	⬆️
...K/Localization/Provider/LocalizationProvider.swift	71.85% <82.15%> (+6.68%)	⬆️
Sources/CrowdinSDK/CrowdinSDK/CrowdinSDK.swift	60.68% <100.00%> (-5.63%)	⬇️
...wdinSDK/CrowdinSDK/Localization/Localization.swift	78.58% <100.00%> (+3.02%)	⬆️
...rowdin/Extensions/CrowdinSDK+CrowdinProvider.swift	41.67% <100.00%> (-8.33%)	⬇️
...tionDownloader/CrowdinLocalizationDownloader.swift	62.50% <100.00%> (+0.80%)	⬆️
... and 15 more

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[crowdin-bot]

	Warnings
⚠️	Big PR, try to keep changes smaller if you can

Generated by 🚫 Danger Swift against 3335a6a

[chrispomeroyhale]

Wow, this was a lot of work @serhii-londar!

I quickly tried this out and still a little unclear when the completion handler gets called? I recall not seeing a completion handler called if, say, the manifest request failed? The resilience of the SDK is important to us. We're needing to access properties like inSDKLocalizations which require full initialization before they are populated.

What is the expectation of the completion handler? Is that the signal for us clients that the SDK has successfully initialized?

[serhii-londar]

HI @chrispomeroyhale, thanks for your feedback!
The completion handler called after SDK get or tried to get all the required files. It means that currently if you initialize SDK without an internet connection completion handler still will be called, all errors you receive via the error handler.

About inSDKLocalizations, now we've added caching for the manifest file so that when you have something cached you are able to get it immediately after starting SDK. After completion called it means that you can access inSDKLocalizations and they are up to date. Same for localizations.