After implementing "collaboration" features in an editor, I discovered that functionality can also be used else-where for example with undo/redo. But also in fo

After implementing "collaboration" features in an editor, I discovered that functionality can also be used else-where for example with undo/redo. But also in for example a web app that has many servers, eg a site like Facebook. For example 1) you get message A, 2) You Read message A 3) You get message A again, which would usually end up with annoying user interface errors, like "you got one undread messages", even though you've read them all. But if you transform the event, that last message, get market as read, because there was a prior event marking it as read.