The Dart collection framework has a usable set of collection classes that exists in the
dart:collection libraries, as shown in the following diagram:
The standard collection interfaces simplify the passing and returning of collections to and from the class methods and allows the methods to work on a wide variety of collections. Using the common collection implementations makes the code shorter and quicker. By adhering to these implementations, you can make your code more standardized and easier to understand for yourself and others.