NSCoding
The NSCoding protocol declares the two methods that a class must implement so that instances of that class can be encoded and decoded. This capability provides the basis for archiving (where objects and other structures are stored on disk) and distribution (where objects are copied to different address spaces).
protocol NSCodingIn keeping with object-oriented design principles, an object being encoded or decoded is responsible for encoding and decoding its instance variables. A coder instructs the object to do so by invoking encode(with:) or init(coder:). encode(with:) instructs the object to encode its instance variables to the coder provided; this method can be invoked any number of times. init(coder:) instructs the object to initialize itself from data in the coder provided. Any object class that should be codable must adopt the NSCoding protocol and implement its methods.