@type t() :: %CouncilEx.RoundResult{
  aggregated: map() | nil,
  duration_ms: non_neg_integer() | nil,
  finished_at: DateTime.t() | nil,
  index: non_neg_integer(),
  member_results: %{required(atom()) => CouncilEx.MemberResult.t()},
  metadata: map(),
  name: atom(),
  started_at: DateTime.t() | nil
}