code: function setupProxy (key) {
      self[key].agent    = httpProxy._getAgent(self[key]);
      self[key].protocol = httpProxy._getProtocol(self[key]);
      self[key].base     = httpProxy._getBase(self[key]);
    }
docs: Setup the necessary instances instance variables for the `target` and `forward` `host:port` combinations used by this instance.  * agent {http[s].Agent} Agent to be used by this instance. * protocol {http|https} Core node.js module to make requests with. * base {Object} Base object to create when proxying containing any https settings.