A class is a data structure that may contain data members (constants and fields), function members (methods, properties, events, indexers, operators, instance constructors, destructors, and static constructors), and nested types. Class types support inheritance, a mechanism whereby a derived class can extend and specialize a base class.
A class-declaration is a type-declaration (§9.6) that declares a new class.
A class-declaration consists of an optional set of attributes (§17), followed by an optional set of class-modifiers (§10.1.1), followed by an optional
partial modifier, followed by the keyword