How can I track *all* changes in the active editor while typing/refactoring/etc?

Hello,

   I want to track all changes, what are happening in the active editor. How can I register a listener on that? So far I have tried two things:

1) creating a new EditorAction (but this requires me to provide a shortcut to work.. or, there is a way to activate action for every keystroke?)
2) I've used VirtualFileManager.getInstance().addVirtualFileListener(), thou it looks too low level for me. I would like to have Document at my hand, not just VirtualFile.

Is there a more correct way of doing that?

Wbr,
Jevgeni