addAll abstract method
void addAll(Adds all elements
to this Set.
Equivalent to adding each element in elements
using add, but some collections may be able to optimize it.
Source
void addAll(Iterable<E> elements);
© 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
https://api.dartlang.org/stable/1.24.3/dart-core/Set/addAll.html