@type t() :: %AshR2RML.SPARQL.Observation{
  endpoint: String.t() | nil,
  evidence_kind: atom(),
  metadata: map(),
  query_form: atom(),
  query_sha256: String.t(),
  result_kind: atom() | nil,
  result_sha256: String.t() | nil,
  rows: list(),
  standing: atom(),
  status: atom(),
  strategy: :local_rdf | :protocol | :ontop_cli
}