Napster

Protocol‘A protocol defines a blueprint of methods, properties, and other requirements that suit a particular task or piece of functionality. The protocol can then be adopted by a class, structure, or enumeration to provide an actual implementation of those requirements’다음에서 발췌: Apple Inc. ‘The Swift Programming Language (Swift 4.0.3).’ iBooks. https://itunes.apple.com/kr/book/the-swift-programm..