gistfile1.swift

// source = MIKMIDIDeviceManager.shared.virtualSources[idx]

try MIKMIDIDeviceManager.shared.connectInput(source) { (source, commands) in
                var numbers = MIDI.numbers

                for case let command as MIKMIDIControlChangeCommand in commands {
                    numbers[safe: Int(command.controllerNumber)] = Float(command.controllerValue) / 127
                }
                
                MIDI.numbers = numbers
            }