Example
If you import two libraries that have conflicting identifiers, then you can specify a prefix for one or both libraries. For example, if library1 and library2 both have an Element class, then you might have code like this:
import 'package:lib1/lib1.dart';
import 'package:lib2/lib2.dart' as lib2;
// ...
var element1 = new Element(); // Uses Element from lib1.
var element2 =
new lib2.Element(); // Uses Element from lib2.
