@type t() :: %ElasticsearchEx.Document{
  _id: nil | binary(),
  _index: nil | binary(),
  _primary_term: nil | pos_integer(),
  _score: nil | float(),
  _seq_no: nil | non_neg_integer(),
  _shards: nil | %{required(atom() | binary()) => non_neg_integer()},
  _source: map(),
  _version: nil | pos_integer(),
  found: nil | boolean(),
  result: nil | binary()
}