I'm writing a patch that takes in MIDI data and uses poly~ and thispoly~ to provide polyphony. Occasionally, though, there is a stuck note. This happens rarely enough that I'm not sure what conditions cause it. I tried sending my poly~ object an "allnotesoff" message to clear the stuck note when it comes up, but that doesn't work. How can I prevent the stuck note, or at least stop it when it happens?