AsyncEx

[TheAngryByrd]

Proposed Changes

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This adds AsyncEx

1. Allows use for IAsyncDisposable
2. Allows let!/do! against Tasks/ValueTasks/any Awaitable
3. When Tasks throw exceptions they will use the behavior described in Async.Await overload (esp. AwaitTask without throwing AggregateException

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

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• I have added tests that prove my fix is effective or that my feature works (if appropriate)
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[bartelink]

@TheAngryByrd the official ATC calls onError, and does not wrapp the inner one
IIRC this has an important impact (the fssnip has tests that expose it). I cant recall whether the bit that breaks this way is

1. Async.Parallel doesn't kill the siblings (as it;'s waiting for the first exception or something?)
2. cancellation is not honored

IIRC there are two separate F# issues that cover the overall requirements (the AggregateException bit vs the Await Cancellation as Exception aspect)

My general conclusion is that we're better off having AwaitTaskCorrect, which has been very well battle proven, with specific failing tests covering any deviation from its entire behavior