An ObjectTracer can be wrapped around another object, and then give you a chance to inspect it whenever it receives messages from the outside. For instance...
(ObjectTracer on: Display) flash: (50@50 extent: 50@50)
will give control to a debugger just before the message flash is sent.
Obviously this facility can be embellished in many useful ways.
See also the even more perverse subclass, ObjectViewer, and its example.

	very few messages	top
	doesNotUnderstand: All external messages (those not caused by the re-send) get trapped here
	xxxUnTrace
	xxxViewedObject This message name must not clash with any other (natch).
	xxxViewedObject: This message name must not clash with any other (natch).

	instance creation	top
	on: