ResolverUtility.FindLibraryFromSourcesAsync should cancel pending work when returning early

[drewnoakes]

https://github.com/NuGet/NuGet.Client/blob/3be9ceed93526e7fed1282820436435694f122cd/src/NuGet.Core/NuGet.DependencyResolver.Core/ResolverUtility.cs#L433-L456

This code spins up one Task per IRemoteDependencyProvider and waits for them to complete.

If one of these tasks completes with an exact match, that match is returned immediately.

However in such a case, any pending work is left to complete. From my reading of the code, the result of that work is unused, and therefore those ongoing tasks should be cancelled to avoid wasting resources (IO/CPU/etc).

If that's right, it can be achieved easily with CancellationTokenSource.CreateLinkedTokenSource.

[ghost]

@drewnoakes Issue is missing Type label, remember to add a Type label

[nkolev92]

The benefits of that idea are probably varied by scenario.

If you have more than 1 version of a package within that solution, then cancelling a task that might be bringing the 2nd version that's in a project that hasn't been restored yet could have a negative impact.
This would probably require some performance testing like for example: https://github.com/NuGet/NuGet.Client/tree/dev/scripts/perftests