Crashed: NSOperationQueue 0x129d86d20 (QOS: UNSPECIFIED)

My app is using firebase crashlytics which provide this issue with a stack trace:

Crashed: NSOperationQueue 0x129d86d20 (QOS: UNSPECIFIED)
0 libdispatch.dylib 0x1861cd8c4 _dispatch_sync_f + 4
1 flutter_downloader 0x101845530 -[FlutterDownloaderPlugin URLSession:downloadTask:didWriteData:totalBytesWritten:totalBytesExpectedToWrite:] + 548
2 CFNetwork 0x189958908 _CFNetworkHTTPConnectionCacheSetLimit + 204440
3 Foundation 0x1869323f0 __NSBLOCKOPERATION_IS_CALLING_OUT_TO_A_BLOCK__ + 16
4 Foundation 0x18683d710 -[NSBlockOperation main] + 84
5 Foundation 0x18693464c __NSOPERATION_IS_INVOKING_MAIN__ + 20
6 Foundation 0x18683d414 -[NSOperation start] + 740
7 Foundation 0x186935044 __NSOPERATIONQUEUE_IS_STARTING_AN_OPERATION__ + 20
8 Foundation 0x186934b10 __NSOQSchedule_f + 180
9 libdispatch.dylib 0x1861d5c8c _dispatch_block_async_invoke2 + 104
10 libdispatch.dylib 0x186223524 _dispatch_client_callout + 16
11 libdispatch.dylib 0x1861cbe98 _dispatch_continuation_pop$VARIANT$mp + 412
12 libdispatch.dylib 0x1861cb5ec _dispatch_async_redirect_invoke + 656
13 libdispatch.dylib 0x1861d8438 _dispatch_root_queue_drain + 376
14 libdispatch.dylib 0x1861d8bf8 _dispatch_worker_thread2 + 124
15 libsystem_pthread.dylib 0x186274b38 _pthread_wqthread + 212
16 libsystem_pthread.dylib 0x186277740 start_wqthread + 8

I'm using version 1.5.2 and my flutter version is:
[✓] Flutter (Channel stable, 1.22.4, on Mac OS X 10.15.1 19B88 darwin-x64, locale en-US)
[✓] Android toolchain - develop for Android devices (Android SDK version 29.0.3)
[✓] Xcode - develop for iOS and macOS (Xcode 11.3)
[✓] Android Studio (version 3.6)
[✓] Connected device (2 available)
• No issues found!

Any idea?

Start at the FlutterDownloaderPlugin URLSession:downloadTask:didWriteData:totalBytesWritten:totalBytesExpectedToWrite: callback named in the crash stack. Reproduce with flutter_downloader 1.5.2 on iOS using the reported Flutter and Xcode versions, then inspect the synchronous dispatch path. Done means identifying the crash trigger and validating a fix with a regression test or reproduction.

Written by the indexing model from the issue text.