code: function serviceCall(req, res, next) {
          connector.runCall(req.params.connection, req.params.call, req.body).then(res.json.bind(res), next).done();
      }
docs: 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.