Function context 

pub fn context(
    store: &Store,
    key: &str,
) -> Result<Option<NodeContext>, StoreError>

Fetch a node’s context through the cache: return the cached bundle when its fingerprint still matches the current graph, otherwise rebuild it, store it, and return the fresh bundle. Returns None (and prunes any stale entry) if the node no longer exists.

Errors

Returns StoreError on query failure, or if a cached entry cannot be decoded.