DasCanvasStateSupport is a registery where objects can tell the canvas they intend to mutate the canvas, so canvas clients should know that its result may be incomplete. This is first introduced to support server-side processing, where in Autoplot the Autolayout feature knows then layout is going to be adjusted, but doesn't have enough information to perform the function. Also, this may be used to address bugs like https://bugs-pw.physics.uiowa.edu/mantis/view.php?id=303, "strange intermediate states in transitions," since canvas painting can be halted while the change is being performed.
someone has registered a pending change.