presto-main/src/main/java/io/prestosql/cost/FilterStatsCalculator.java/FilterStatsCalculator/visitFunctionCall
class FilterStatsCalculator:        @Override
        protected PlanNodeStatsEstimate visitFunctionCall(FunctionCall node, Void context)
        {
            if (isDynamicFilter(metadata, node)) {
                return process(BooleanLiteral.TRUE_LITERAL, context);
            }
            return PlanNodeStatsEstimate.unknown();
        }