public static void AddCallback(ImDrawListPtr drawList, CustomDrawEvent callback, object args = null)
{
int index = ImGuiDelegates.Count + 1;
int dataIndex = ImGuiDelegateArgs.Count + 1;
ImGuiDelegates.Add(callback);
ImGuiDelegateArgs.Add(args);
drawList.AddCallback((IntPtr)index, (IntPtr)dataIndex);
}