-type encode_param() ::
          ping | pong | ok | error |
          {info, iodata()} |
          {connect, iodata()} |
          error_param() |
          pub_param() |
          hpub_param() |
          sub_param() |
          unsub_param() |
          msg_param() |
          hmsg_param().

-type error_param() ::
          {error, unknown_operation} |
          {error, auth_violation} |
          {error, auth_timeout} |
          {error, parser_error} |
          {error, stale_connection} |
          {error, slow_consumer} |
          {error, max_payload} |
          {error, invalid_subject}.

-type hmsg_param() ::
          {hmsg,
           {Subject :: iodata(),
            Sid :: iodata(),
            ReplyTo :: iodata() | undefined,
            Header :: iodata(),
            Payload :: iodata()}}.

-type hpub_param() ::
          {hpub,
           {Subject :: iodata(),
            ReplyTo :: iodata() | undefined,
            Header :: iodata(),
            Payload :: iodata()}}.

-type msg_param() ::
          {msg,
           {Subject :: iodata(), Sid :: iodata(), ReplyTo :: iodata() | undefined, Payload :: iodata()}}.

-type pub_param() :: {pub, {Subject :: iodata(), ReplyTo :: iodata() | undefined, Payload :: iodata()}}.

-type sub_param() :: {sub, {Subject :: iodata(), QueueGrp :: iodata() | undefined, Sid :: iodata()}}.

-type unsub_param() :: {unsub, {Sid :: iodata(), MaxMsg :: integer() | undefined}}.