- 父类是NSObject
NSCoder的方法
- (void)encodeValueOfObjCType:(const char *)type at:(const void *)addr;
- (void)encodeDataObject:(NSData *)data;
- (void)decodeValueOfObjCType:(const char *)type at:(void *)data;
- (nullable NSData *)decodeDataObject;
- (NSInteger)versionForClassName:(NSString *)className;
