removeAll method
Removes all the children in the list and calls onRemove for all of them
and their children.
Implementation
void removeAll(Iterable<Component> components) {
  components.toList(growable: false).forEach(_removeChild);
}Removes all the children in the list and calls onRemove for all of them
and their children.
void removeAll(Iterable<Component> components) {
  components.toList(growable: false).forEach(_removeChild);
}