Function build_threshold_basic

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

Build a dataflow to threshold the input data.

This implementation maintains rows in the output, i.e. all rows that have a count greater than zero. It returns a CollectionBundle populated from a local arrangement.