4.5. Struct Model# TODO 4.5.1. Sequence Sequence 4.5.2. Struct 4.5.2.1. The Struct class 4.5.2.2. Unions 4.5.2.3. Standard Interface 4.5.2.4. Struct Mixins 4.5.3. Bitfield 4.5.3.1. Main Interface 4.5.3.2. Default Factory Classes 4.5.3.3. Default Options 4.5.3.4. Bitfield Mixins 4.5.4. Templates TemplateTypeVar istemplate() template() derive()