Why doesn't the whole folder work at the root when using UseFileServer in OWIN?

I am creating a simple demo application where I want to use extensions StaticFile

. To set it up, I have the following code:

app.UseFileServer(new FileServerOptions()
{
        FileSystem = new PhysicalFileSystem(@".\content"),
        RequestPath = PathString.Empty,
        EnableDefaultFiles = true
});

      

        
        
        
      

    

In a folder content

I have index.html

which is the server itself when I visit /

as expected, but the files are not served as expected.

content
    index.html
    app
        lib
            something.js

      

        
        
        
      

    

This is the file structure I have and I want to access something.js

by url /app/lib/something.js

, but with the code I have I now need to use /content/app/lib/something.js

which I don't want. Why index.html

does it get directly when I visit /

, but not when I go to /index.html

, and the same goes for the js file.