I'm currently working with ASP.NET core 3.1 and C# 8.
This is the very first time that I'm touching on the whole IAsyncDisposable story, so it is entirely possible that my understanding is only partial and that this question is a dumb one.
Based on my understanding a type should implement the IAsyncDisposable interface when it needs to release the resources that it owns in an asyncronous way, so that the required disposal can be carried on without blocking a thread. Put another way, IAsyncDisposable is the asyncronous counterpart of IDisposable which allows to release class resources in an efficient manner (in terms of threads usage).
The language supports the consumption of types implementing the IAsyncDisposable by means of the new await using construct, which is basically the asyncronous counterpart of the using keyword.
So far so good.
I have noticed that there are some BCL types which implements both IAsyncDisposable and IDisposable, one of them being the Stream abstract class. I have encountered this scenario while working on uploaded files in ASP.NET core and calling the IFormFile.OpenReadStream method.
My question now is the following: how should I consume a type implementing both IAsyncDisposable and IDisposable ? Should I use the classic using keyword or should I opt for await using ?
The piece of code I was writing is a syncronous one, so the most natural way to deal with the stream is the following:
using var readStream = uploadedFile.OpenReadStream();
var options = new LoadOptions(loadFormat);
return new Workbook(readStream, options);
Should I make my method async in order to being able to use await using in the following manner ?
await using var readStream = uploadedFile.OpenReadStream();
var options = new LoadOptions(loadFormat);
return new Workbook(readStream, options);
(consider that, apart the await using call, my method does not need to be asyncronous)
What is the difference in calling Dispose versus DisposeAsync for a type implementing both of them ?