State of the RDF.Canonicalization algorithm.
RDF.Canonicalization
https://www.w3.org/TR/rdf-canon/#canon-state
@type t() :: %RDF.Canonicalization.State{ bnode_to_quads: term(), canonical_issuer: term(), hash_algorithm: term(), hash_to_bnodes: term(), hndq_call_limit: term() }