`FileSystemStream` Issues

[JasonBock]

Describe the bug
There's a documentation and API issue with this type. There isn't a way to reproduce this, more that the design should be reviewed.

• The XML docs say Wraps the <see cref="FileStream" />, but the wrapped field, _stream, is of type Stream. There's no runtime check to ensure that the stream provided in the constructor is of type FileStream. This is confusing because the docs state one thing, but the implementation doesn't seem to match that.
• The path parameter for the constructor is defined as string?, but the constructor will throw an ArgumentNullException if path is null. This is confusing, as annotating a parameter as nullable means that the method can accept a null value. If path cannot be null, then remove the nullable annotation.

[vbreuss]

Thanks for the hint @JasonBock.

The intention of this class is to wrap the FileStream but make it testable. So the interface wraps the FileStream and in the "normal" usage in production the provided stream should be a FileStream.
Only in the testing wrapper, we will replace it with a different stream for testing purposes.
I agree, that the XML documentation is short and could be improved, but the intention of it wrapping a FileStream is in essence correct.

With your second point I agree completely. The path parameter should be string.

A pull request would be welcome!

[ZaffyPuck]

Hi, I am a college student looking trying to get more involved with open source and looking for a first-time "bug fix" and figured I could help out with this! I am a little confused with what XML docs you are referring to. Perhaps a link would help. As for the string issue, it should be string as opposed to string? because you want the user to pass data through the constructor. Is there anything I could help with as far as fixing the documentation or code? Let me know!

[vbreuss]

@ZaffyPuck : The second point was already fixed in #956!
A link to the file is mentioned in the description.