Listing 9-12 extracted from chapter Fundamental concepts of the language

Listing 9-11<     > Listing 9-13

This listing can be compiled with the command line:
csc.exe /out:Asm2.dll /target:library Example_9_12_to_rename_Asm2.cs
Errors: 0 Warnings: 0

namespace Custom.IO{ public class Stream{} }
namespace FooIO{ public class Stream{} }