public ButtonBarPagerTabStripViewController(string nibName, NSBundle bundle) : base(nibName, bundle)
        {
            Delegate   = this;
            DataSource = this;
            Func <IndicatorInfo, nfloat> widthCallback = GetWidth;

            ButtonBarItemSpec = ButtonBarItemSpec <ButtonBarViewCell> .Create(widthCallback, "ButtonCell", null);
        }
        public ButtonBarPagerTabStripViewController()
        {
            Delegate   = this;
            DataSource = this;
            Func <IndicatorInfo, nfloat> widthCallback = GetWidth;

            ButtonBarItemSpec = ButtonBarItemSpec <ButtonBarViewCell> .Create(widthCallback, "ButtonCell", NSBundle.FromClass(new ObjCRuntime.Class(typeof(ButtonBarViewCell))));
        }
        public ButtonBarPagerTabStripViewController(NSCoder coder) : base(coder)
        {
            Delegate   = this;
            DataSource = this;
            Func <IndicatorInfo, nfloat> widthCallback = GetWidth;

            ButtonBarItemSpec = ButtonBarItemSpec <ButtonBarViewCell> .Create(widthCallback, "ButtonCell", null);
        }