docs: function init(app) {
      app.post('/api/v1/connectors/:connection', 
      /**
       * installs session data such as credentials.
       *
       * @param req containing body JSON to pass as input.
       * @param res result of call is provided as JSON body data.
       * @param next function to invoke error handling.
       */
      function serviceCall(req, res, next) {
          connector.configureSession(req.params.connection, req.body);
          res.send(204); // success --> 204 no content
      });
      app.post('/api/v1/connectors/:connection/:call', 
      /**
       * calls directly into a service connection.
       *
       * @param req containing body JSON to pass as input.
       * @param res result of call is provided as JSON body data.
       * @param next function to invoke error handling.
       */
      function serviceCall(req, res, next) {
          connector.runCall(req.params.connection, req.params.call, req.body).then(res.json.bind(res), next).done();
      });
  }