Function compose 

pub fn compose(
    projection: &Projection,
    params: &Params,
    canonical_target: &Path,
    stage_root: &Path,
    record: Option<&Manifest>,
    dropped: &[Decision],
    receipt_schema_version: Option<u64>,
) -> Composed

Compose the stage for projection, rooted at stage_root.

It draws on the projection, the resolved parameters, the target’s record, the landing’s decision for every recorded destination the projection no longer produces, and this binary’s embedded knowledge.