Remove default value for accessMode flag in IFile

[d2dyno1]

The problem

The current IFile interface contains a function OpenStreamAsync() which opens the file in read-only mode.

public Task<Stream> OpenStreamAsync(FileAccess accessMode = FileAccess.Read, CancellationToken cancellationToken = default);

This might cause erroneous behavior when trying to open a file in a read-write mode without an indication of it.

The solution

Remove the default flag for the accessMode parameter:

public Task<Stream> OpenStreamAsync(FileAccess accessMode, CancellationToken cancellationToken = default);

and let the user create additional extension methods (OpenReadAsync(), OpenWriteAsync()) for opening the file at their own discretion.

[Arlodotexe]

We can for sure create extension methods for OpenReadAsync and OpenWriteAsync/OpenReadWriteAsync.

As for removing the default value here, after thumbing through the official dotnet APIs (e.g. FileStream, File.Open, etc), I'm inclined to agree. Conceptually, just opening a stream to a resource implies nothing about the read/write preferences for that resource, so a default value shouldn't be used here.

This will be a very broad-impact breaking change and will affect both implementors and consumers everywhere IFile is used.

We should have more discussion on this before committing to a timeline for this change, I'd like to hear from others. Update: We'll make this part of the next breaking batch.