The .NET framework provides several ways of interacting with I/O out of the box. These work great until you need to maximize performance over network I/O. Dave Thomas has demonstrated that using SocketAsyncEventArgs rather than the Asynchronous Programming Model (APM) can drastically reduce memory usage and garbage collector shred. Unfortunately, all of the built-in types -- Stream, TextReader, etc. -- provide only the APM as an asynchronous option.

Oleg Kiselyov (Haskell) discovered the iteratee, a left-fold with a few new tricks. Learn about iteratees (consumers), enumerators (producers), and enumeratees, as well as how these provide safe, fast, and efficient I/O for high-performance server applications.