toMap method
Returns the list as a map, with the labels as keys, and the elements as values.
Any elements that don't have a label will have their index as the key.
Implementation
Map<String, E> toMap() {
final map = <String, E>{};
for (var i = 0; i < length; i++) {
map.addAll({_labels[i] ?? i.toString(): elements[i]});
}
return map;
}