How to change Flutter checkbox to use a circle instead of a rounded rectangle

A modifed version of the exisiting checkbox to use a circle instead of a rounded rectangle!

CircularCheckBox(
          value: someBooleanValue,
          materialTapTargetSize: MaterialTapTargetSize.padded,
          onChanged: (bool x) {
          someBooleanValue = !someBooleanValue;
          }
        ),