RazorDocument - [0..13)::13 - [@using Foo   ]
    MarkupBlock - [0..13)::13
        MarkupTextLiteral - [0..0)::0 - [] - Gen<Markup> - SpanEditHandler;Accepts:Any
            Marker;[];
        CSharpCodeBlock - [0..10)::10
            RazorDirective - [0..10)::10
                CSharpTransition - [0..1)::1 - Gen<None> - SpanEditHandler;Accepts:None
                    Transition;[@];
                RazorDirectiveBody - [1..10)::9
                    CSharpStatementLiteral - [1..10)::9 - [using Foo] - Gen<Import: Foo;> - SpanEditHandler;Accepts:AnyExceptNewline
                        Keyword;[using];
                        Whitespace;[ ];
                        Identifier;[Foo];
        MarkupTextLiteral - [10..13)::3 - [   ] - Gen<Markup> - SpanEditHandler;Accepts:Any
            Whitespace;[   ];
