Xs_protocol.Tokenval to_debug_string : t -> stringto_string token is a debug-printable version of token.
val to_user_string : t -> stringto_user_string token is the user-supplied part of token.
val of_string : string -> tof_string str_rep is the token resulting from the unmarshalling of str_rep.
val to_string : t -> stringto_string token is the marshalled representation of token.