Creates a List containing the elements of this Iterable.
The elements are in iteration order.
The list is fixed-length if growable is false.
Source
List<E> toList({bool growable: true}) {
List<E> result = growable ? (new List<E>()..length = length)
: new List<E>(length);
int i = 0;
for (E element in this) result[i++] = element;
return result;
}