Dart APIunself_componentUnmojiheight height property Null safety double? height final Implementation final double? height; unself_component unself_component Unmoji height property Unmoji class Constructors Unmoji Properties emoji fit hashCode height key runtimeType twemojiFormat unicode width Methods build createElement debugDescribeChildren debugFillProperties noSuchMethod toDiagnosticsNode toString toStringDeep toStringShallow toStringShort Operators operator ==