public DetailsPage(Speaker speaker)
        {
            InitializeComponent();

            //Set local instance of speaker and set BindingContext
            this.speaker = speaker;
            BindingContext = this.speaker;
        }
        public DetailsPage(Speaker item)
        {
            InitializeComponent();
            this.speaker = item;

            BindingContext = this.speaker;

            ButtonSpeak.Clicked += ButtonSpeak_Clicked;

            ButtonWebsite.Clicked += ButtonWebsite_Clicked;
        }