addAll method

void addAll (Iterable<E> iterable)

Appends all objects of iterable to the end of this list.

Extends the length of the list by the number of objects in iterable. Throws an UnsupportedError if this list is fixed-length.

Implementation 

void addAll(Iterable<E> iterable) {
  int i = this.length;
  for (E element in iterable) {
    assert(this.length == i || (throw new ConcurrentModificationError(this)));
    this.length = i + 1;
    this[i] = element;
    i++;
  }
}