code: public static ParticipantCreator creator(final String pathServiceSid, 
                                               final String pathSessionSid, 
                                               final String identifier) {
          return new ParticipantCreator(pathServiceSid, pathSessionSid, identifier);
      }
docs: Create a ParticipantCreator to execute create.
  
  @param pathServiceSid The SID of the parent Service resource
  @param pathSessionSid The SID of the parent Session resource
  @param identifier The phone number of the Participant
  @return ParticipantCreator capable of executing the create