Method with_udaf

datafusion/optimizer/tests/optimizer_integration.rs:846–850

(mut self, udaf: Arc<AggregateUDF>)

impl MyContextProvider {
    fn with_udaf(mut self, udaf: Arc<AggregateUDF>) -> Self {
        // TODO: change to to_string() if all the function name is converted to lowercase
        self.udafs.insert(udaf.name().to_lowercase(), udaf);
        self
    }

    fn with_expr_planners(mut self, expr_planners: Vec<Arc<dyn ExprPlanner>>) -> Self {
        self.expr_planners = expr_planners;