Dart APIsettings_listSettingsListSliveronSelectTerms onSelectTerms property Null safety VoidCallback onSelectTerms final Implementation final VoidCallback onSelectTerms; unself_settings_list settings_list SettingsListSliver onSelectTerms property SettingsListSliver class Constructors SettingsListSliver Properties children hashCode key onSelectAppearance onSelectData onSelectFeedback onSelectLicense onSelectPrivacy onSelectTerms runtimeType Methods build createElement debugDescribeChildren debugFillProperties noSuchMethod toDiagnosticsNode toString toStringDeep toStringShallow toStringShort Operators operator ==