Analizo::Metric::ResponseForClass - Response for Class (RFC) metric
The metric calculation is based on the following article and calculates the sum between the number of methods in the module and the number of functions called by each module function.
Article: A metrics suite for object oriented design by Shyam R. Chidamber and Chris F. Kemerer.
See the paragraph about Response for Class in the article:
... The response set of a class is a set of methods that can potentially be executed in response to a message received by an object of that class. The cardinality of this set is a measure of the attributes of objects in the class. Since it specifically includes methods called from outside the class, it is also a measure of the potential communication between the class and other classes.