[csharp][netcore] Handle Deserialization Asynchronously

[Blackclaws]

Gets rid of non async pathways that were in the middle of async pathways.

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[wing328]

cc @lucamazzanti as well (new C# technical committee member)

[lucamazzanti]

Another emprovement you can put in this PR is the .ConfigureAwait(false) after each Async method.

Use ConfigureAwait(false) , especially if you are implementing a library method, as it will avoid running a continuation on the original context. For library methods, it is a must, as they should never depend on the calling/original context for the continuation.

There are a lot of sources about that, here some links:

• articles: https://medium.com/bynder-tech/c-why-you-should-use-configureawait-false-in-your-library-code-d7837dce3d7f
• books: https://www.amazon.it/Enterprise-Application-Development-NET-professional-grade/dp/1800209444/ref=sr_1_1?__mk_it_IT=%C3%85M%C3%85%C5%BD%C3%95%C3%91&dchild=1&keywords=enterprise+application&qid=1621434256&sr=8-1
• libraries: https://github.com/firenero/AsyncIO/blob/master/AsyncIO/FileSystem/AsyncFile.cs

[Blackclaws]

Another emprovement you can put in this PR is the .ConfigureAwait(false) after each Async method.

Use ConfigureAwait(false) , especially if you are implementing a library method, as it will avoid running a continuation on the original context. For library methods, it is a must, as they should never depend on the calling/original context for the continuation.

There are a lot of sources about that, here some links:

* articles: https://medium.com/bynder-tech/c-why-you-should-use-configureawait-false-in-your-library-code-d7837dce3d7f

* books: https://www.amazon.it/Enterprise-Application-Development-NET-professional-grade/dp/1800209444/ref=sr_1_1?__mk_it_IT=%C3%85M%C3%85%C5%BD%C3%95%C3%91&dchild=1&keywords=enterprise+application&qid=1621434256&sr=8-1

* libraries: https://github.com/firenero/AsyncIO/blob/master/AsyncIO/FileSystem/AsyncFile.cs

Hmm. The deserialization is in general only called from another library internal async method anyway. ConfigureAwait(false) is already called at the level of Api. So I'm not sure if it would add anything to sprinkle it all over the codebase here. We might want to do a general review of the async functionality in the generated code however.