Temporarily disable Event callback

I have a Buffer and I want to change its text without any on_text_changed events being fired. Is this currently possible without too much hacking?

I've tried adding this simple context manager to the Event class and it seems to work well. Should I make a PR?

@property
def handlers_disabled(self):
    """
    Context manager that disables all event handlers in its `with` block
    """
    class contextmanager:
        def __enter__(self, event=self):
            self._handlers = event._handlers
            event._handlers = []

        def __exit__(self, *exc_, event=self):
            event._handlers = self._handlers

    return contextmanager()

BTW: This is an awesome project. It's one of those things I never knew I badly needed.

Start by locating the Event class and Buffer's on_text_changed path; the issue does not name files or tests. Check how handlers are stored and invoked, then add coverage for temporarily suppressing callbacks and verify normal callbacks resume afterward.