Function mz_compute::render::threshold::build_threshold_retractions

pub fn build_threshold_retractions<G, T>(
    input: CollectionBundle<G, Row, T>,
    key: Vec<MirScalarExpr>
) -> CollectionBundle<G, Row, T>where
    G: Scope,
    G::Timestamp: Lattice + Refines<T>,
    T: Timestamp + Lattice,

Build a dataflow to threshold the input data while maintaining retractions.

This implementation maintains rows that are not part of the output, i.e. all rows that have a count of less than zero. It returns a CollectionBundle populated from the output collection, which itself is not an arrangement.