This class is defined as an abstract mixin class. It must be implemented by subclassing it or inheriting from it as a mixin. Many of the methods in this class are abstract and must be overridden or they will throw a syntax error when invoked.
The class InputOutputStream is a mixin class (it can be inherited by other classes), it subclasses (specializes) The Object Class and inherits (specializes) in addition in the following order: