Timing.withinNoteList constructor
Create a Timing for a Note using Timing.unspecified based on the index of the Note in a List
Implementation
factory Timing.withinNoteList(
{required int listLength, required int noteIndex}) {
assert(noteIndex > -1 && noteIndex < listLength);
return Timing(notesPerMeasureToNoteType(listLength), noteIndex + 1);
}