Function diff_schema 

pub fn diff_schema(
    destination: &Value,
    page: &Value,
    allow_widening: bool,
) -> SchemaDiff

Diff a page’s inferred shape against the destination schema (top-level columns).

destination and page are both infer_schema-shaped object schemas ({"type":"object","properties":{...}}). allow_widening gates whether a lossless widening lands in widenings (true) or incompatible (false).