Expand description
PathMap: a map keyed by option path, stored as a vector sorted by key.
It stands in for BTreeMap<String, V> where the policy proofs read the
keys: vstd only specifies BTreeMap for key types with an ordering spec,
which String lacks, while a Vec is specified unconditionally. The
methods keep the entries sorted and unique; the proofs do not depend on
that, only on which keys are present. Serialized as a JSON object, as the
BTreeMap was.