Class GeneratedMessageV3.UnusedPrivateParameter (3.19.4)

This class is used to make a generated protected method inaccessible from user's code (e.g., the #newInstance method below). When this class is used as a parameter's type in a generated protected method, the method is visible to user's code in the same package, but since the constructor of this class is private to protobuf runtime, user's code can't obtain an instance of this class and as such can't actually make a method call on the protected method.