[PLAT-8819] Add leaveNetworkRequestBreadcrumbForTask:metrics:

[nickdowell]

Goal

Facilitate leaving network request breadcrumbs without relying on the plugin's Objective-C method swizzling.

• BugsnagNetworkRequestPlugin manual logging support (no swizzling) #1420

Design

+[Bugsnag leaveNetworkRequestBreadcrumbForTask:metrics:] provides a public API for leaving a network request breadcrumb based on an NSURLSessionTask and NSURLSessionTaskMetrics.

Changeset

Adds +[Bugsnag leaveNetworkRequestBreadcrumbForTask:metrics:] and -[BugsnagClient leaveNetworkRequestBreadcrumbForTask:metrics:].

Moves breadcrumb message & metadata computation from BSGURLSessionTracingDelegate to BSGNetworkBreadcrumb.m, called from -[BugsnagClient leaveNetworkRequestBreadcrumbForTask:metrics:].

Calls -[BugsnagClient leaveNetworkRequestBreadcrumbForTask:metrics:] from -[BSGURLSessionTracingDelegate URLSession:task:didFinishCollectingMetrics:].

Testing

Migrates and modifies existing unit tests to continue passing.

Verified by existing E2E scenario.

[github-actions]

Bugsnag.framework binary size increased by 1,200 bytes from 757,472 to 758,672

    FILE SIZE        VM SIZE    
 --------------  -------------- 
  +1.2% +2.70Ki  +1.2% +2.70Ki    __TEXT,__text
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  +1.1%    +224  +1.1%    +224    __DATA,__cfstring
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  +2.2%    +144  +2.2%    +144    __DATA,__objc_selrefs
  +4.1%     +48  +4.1%     +48    Export Info
  +0.1%     +48  +0.1%     +48    __DATA,__objc_const
  +1.4%     +40  +1.4%     +40    Binding Info
  +0.4%     +12  +0.4%     +12    __TEXT,__unwind_info
  +0.5%      +8  +0.5%      +8    Function Start Addresses
  +1.3%      +8  +1.3%      +8    __DATA,__objc_classrefs
  -3.0%    -424  -9.4%    -424    [__DATA]
  [ = ]       0  -9.5% -1.17Ki    [__LINKEDIT]
 -11.6% -3.19Ki -11.6% -3.19Ki    [__TEXT]
  +0.2% +1.17Ki  [ = ]       0    TOTAL

Generated by 🚫 Danger

[eseay]

Thank you for doing this! A great addition!