pub fn flatten_embedded<Doc: Serialize, R>(
documents: Vec<(Doc, Vec<Embedding>)>,
f: impl FnMut(&Value, Embedding) -> Result<R, VectorStoreError>,
) -> Result<Vec<R>, VectorStoreError>Expand description
Serializes each document to JSON once, then applies f to every
(document, embedding) pair, flattening the results into a single vector.
This is the shared shape of most InsertDocuments implementations:
build one backend record per embedding, carrying the owning document’s
serialized form.