Function to call when a MIDI note-on event is received (e.g. for turning on your synth). Attack velocity is from 0 to 127. Must return a note-off callback (e.g. for turning off your synth).
Function to call when a MIDI note-on event is received (e.g. for turning on your synth). Attack velocity is from 0 to 127. Must return a note-off callback (e.g. for turning off your synth).