1. override
Iterable map(dynamic f(E e))

Returns a new lazy Iterable with elements that are created by calling f on each element of this Iterable in iteration order.

This method returns a view of the mapped elements. As long as the returned Iterable is not iterated over, the supplied function f will not be invoked. The transformed elements will not be cached. Iterating multiple times over the returned Iterable will invoke the supplied function f multiple times on the same element.

Methods on the returned iterable are allowed to omit calling f on any element where the result isn't needed. For example, elementAt may call f only once.

Source 

@override
Iterable<dynamic/*=T*/> map/*<T>*/(/*=T*/ f(E e)) {
  return new CachingIterable<dynamic/*=T*/>(super.map/*<T>*/(f).iterator);
}