Function field_order 

pub fn field_order(a: &str, b: &str) -> Ordering

The order a record keeps its fields in.

Fields is sorted by name and that order is load-bearing far outside this module — it is a Map’s iteration, the state digest, the patch stream and the order Ord compares two records in. A backend that lays a record out in memory has to lay it out in this order or its < disagrees with the evaluator’s, so the order is published rather than reimplemented.