Dart APIunself_styleUnSymbolSizesXS XS constant Null safety double const XS Implementation static const XS = 16.0; unself_style unself_style UnSymbolSizes XS constant UnSymbolSizes class Constructors UnSymbolSizes Properties hashCode runtimeType Methods noSuchMethod toString Operators operator == Constants emojiL emojiM emojiXL Full L M None S XL XS