Function mz_compute::render::reduce::build_distinct

fn build_distinct<G>(
    debug_name: &str,
    collection: Collection<G, (Row, Row), Diff>
) -> (Arranged<G, TraceAgent<ColValSpine<Row, Row, <G as ScopeParent>::Timestamp, Diff, usize>>>, Collection<G, DataflowError, Diff>)where
    G: Scope,
    G::Timestamp: Lattice,

Build the dataflow to compute the set of distinct keys.