fix See merge request upm-packages/ui-widgets/com.unity.uiwidgets!169
font.hideFlags = HideFlags.DontSave & ~HideFlags.DontSaveInBuild;
FontInfo current;
var name = font.name;
this._fonts.TryGetValue(fontRef, out current);
D.assert(current == null || current.font == font, $"font with key {fontRef} already exists");
var fontInfo = new FontInfo(font);