Mainlining custom native features

[JoshuaMoelans]

We're working to integrate the following features which a custom Native-SDK setup shared with us had already implemented.

Currently mainlining

• (Crashpad) Enabling report-retry mechanism for all platforms
  feat(crashpad): enable report retry-mechanism for all platforms #1152
• (Crashpad) Delaying shutdown until upload thread completes
  feat(crashpad): add option to delay shutdown until crash report upload completes (Linux) #1153

To be discussed

• Storing failed transport envelopes on Disk
• Explicit envelope sending and deserialization

See also

• Support Offline Caching of Envelopes #1316
• Document delivery guarantees of Native SDK transports #1186
• Sending captured events should honor sending fail. #932

[JoshuaMoelans]

We have now mainlined the first two features. The next step is to discuss the remaining two, and to decide in what capacity these should be implemented.

The storing of failed transport envelopes ties in with this docs issue about documenting delivery guarantees of Native SDK transports (#1186)