@type t() :: %QuackDB.Profile.Operator{
  children: [t()],
  cpu_time: number() | nil,
  cumulative_cardinality: non_neg_integer() | nil,
  cumulative_rows_scanned: non_neg_integer() | nil,
  extra_info: map(),
  operator_cardinality: non_neg_integer() | nil,
  operator_name: String.t() | nil,
  operator_rows_scanned: non_neg_integer() | nil,
  operator_timing: number() | nil,
  operator_type: String.t() | nil,
  result_set_size: non_neg_integer() | nil,
  system_peak_buffer_memory: term(),
  system_peak_temp_dir_size: term()
}