Essential .NET, Volume 1: The Common Language Runtime

Message Processing (Revisited)

The previous section illustrated how a custom proxy can pre- and postprocess method calls simply by getting between the transparent proxy and the stack builder sink. What if one wanted to inject more than one stage of pre- and postprocessing? Yes, one could simply layer proxy upon proxy; however, redundant stack-to-message transitions would occur at each stage, resulting in undue performance costs. A far preferable approach is to chain together processing stages at the message level, thus paying the cost of stack-to-message transition only once per call and not once per stage per call. This technique is based on message sinks. To facilitate this in a generic manner, the CLR defines the System.Runtime.Remoting.Messaging.IMessageSink ...