Dart APIunself_styleUnSymbolSizesS S constant Null safety double const S Implementation static const S = 20.0; unself_style unself_style UnSymbolSizes S constant UnSymbolSizes class Constructors UnSymbolSizes Properties hashCode runtimeType Methods noSuchMethod toString Operators operator == Constants emojiL emojiM emojiXL Full L M None S XL XS