Hi, I see that the class CalciteConnectionConfigImpl has several useful methods to retrieve information about whether approximate results are acceptable. For example, the approximateDistinctCount method was added in CALCITE-1587. As far as I can see, the Druid adapter doesn't use this method to determine whether to push a count distinct into the Druid query using the cardinality aggregator. I'd like to add this functionality into the Druid adapter as an addition to DruidAggregateRule. Any thoughts or suggestions before I begin? Thanks,Zain.
