lib/response.js
function Response (ghosttrain, callback) {
  this.charset = '';
  this.headers = {};
  this.statusCode = 200;

  this.app = ghosttrain;
  this._callback = callback;
}
function Response (ghosttrain, callback) {
  this.charset = '';
  this.headers = {};
  this.statusCode = 200;

  this.app = ghosttrain;
  this._callback = callback;
}
Shims features of Express's `response` object in routes.
Accepts a `callback` function to be called with the data to send.

@param {Object} ghosttrain
@param {Function} callback
@return {Object}