LHO is seeing DARM/ ETMX L3 "glitches" ~500ms before lockloss

e.g. https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=73818

https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=73565

https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=78479

Would want a new plug in to check for this.

Might tricky to code something that would pick up glitches but not continuous motion from an EQ. Maybe a similar standard deviation check as in refine.py