Flunetui - Custom css rendering on ComboBox

Flunetui TextField has a prop for onRenderSuffix where I can render a Spinner component to indicate that a save call is being made. However, comboBox doesn't have something like that from looking at the IComboBoxProps interface. Any idea how I can implement the following like I am doing with textBox?

onRenderSuffix: () => {
            return (
                <>
                    {isSubmitting && (
                        <TooltipHost
                            id="goal-saving-id"
                            content="some content"
                        >
                            <Spinner aria-describedby="goal-saving-id" />
                        </TooltipHost>
                    )}
                </>
            );
        }`