t :: %Easypost.Tracker{id: String.t, object: String.t, mode: String.t, tracking_code: String.t, status: String.t, created_at: String.t, updated_at: String.t, signed_by: String.t, weight: number, est_delivery_date: String.t, shipment_id: String.t, carrier: String.t, tracking_details: [map]}