This is used by MIDIMessageDispatcherNV to match incoming MIDI messages to instances of MIDIFunc or MIDIdef using message source. This class is private, and generally users should not need to address instances directly.
Check to see if a message matches, and evaluate func if it does.
The message number (e.g. note number, etc.) of the MIDI message as an Integer. Note this should be in the range 0-127.
The channel number of the MIDI message as an Integer. Note this should be in the range 0-15.
The UID of the source of the MIDI message as an Integer.