[xdebug-general] dynamic breakpoint

One feature I would like is something I call "dynamic breakpoint".
What I mean by this is:
getting xdebug to break execution and start debugging when a specified
variable has changed value, or set to a specific value, regardless of
where in the code this happens. So you can't set the breakpoint at a
specific line, because the line could change on every execution.

Is this possible to do?

/Are