animationDuration property
Specifies the duration of the pointer animation.
Duration is defined in milliseconds.
Defaults to 1000.
Widget build(BuildContext context) {
   return Container(
       child: SfRadialGauge(
         axes:<RadialAxis>[RadialAxis(
            pointers: <GaugePointer>[MarkerPointer(value: 50,
            enableAnimation: true, animationDuration: 2000 )],
           )]
       ));
}
Implementation
@override
final double animationDuration;