@type t() :: %Dimse.Pdu.AssociateRq{
  application_context: String.t() | nil,
  called_ae_title: String.t() | nil,
  calling_ae_title: String.t() | nil,
  presentation_contexts: [Dimse.Pdu.PresentationContext.t()] | nil,
  protocol_version: pos_integer() | nil,
  user_information: Dimse.Pdu.UserInformation.t() | nil
}