I'm trying to create a MIDI Thru connection that filters out specific control messages. I'm coding in Swift on macOS 11 and a Swift beginner. The MIDIThruConnectionParams structure is variable length. The MIDIControlTransform type is defined but I am not clear how to add them. Is there a recommended / best / safest way? There is this comment after the structure definition: // remainder of structure is variable-length: //      MIDIControlTransform    controls[]; //      MIDIValueMap            maps[];