How can I find the Text (width/length/ending point) in CanvasDevice via CanvasDrawingSession

fontFamilyName = $"ms-appx:///Assets/HelveticaNeue-Bold.ttf";

CanvasTextFormat FNtextFormat = new CanvasTextFormat

                                {

                                    FontSize = CardTheme.FN.FS,

                                    FontWeight = FNfontWeight,

                                    FontFamily = fontFamilyName,

                                    HorizontalAlignment = CanvasHorizontalAlignment.Left,

                                    VerticalAlignment = CanvasVerticalAlignment.Center

                                };