Dart APIunself_componentChipEmojionSelected onSelected property Null safety ValueChanged<bool>? onSelected final Implementation final ValueChanged<bool>? onSelected; unself_component unself_component ChipEmoji onSelected property ChipEmoji class Constructors ChipEmoji Properties emoji hashCode isEnabled key onSelected runtimeType selected Methods build createElement debugDescribeChildren debugFillProperties noSuchMethod toDiagnosticsNode toString toStringDeep toStringShallow toStringShort Operators operator ==