public virtual void OnFocuserStateChanged(FocuserStateChangedEventArgs e)
 {
     if (FocuserStateChanged != null)
     {
         FocuserStateChanged(this, e);
     }
 }
 private void FocuserStateChanged(object sender, FocuserStateChangedEventArgs e)
 {
     SetCurrentState(e.IsMoving);
 }