docs: function MixpanelClient() {
    var args      = Array.prototype.slice.call(arguments)
      , APIToken  = typeof args[0] === 'string' 
                      ? args.shift() 
                      : undefined
  
      , APIKey  = typeof args[0] === 'string' 
                      ? args.shift() 
                      : undefined
  
      , APISecret  = typeof args[0] === 'string' 
                      ? args.shift() 
                      : undefined
  
      , req       = args.shift()
      , res       = args.shift()
      ;
  
    this.APIToken = APIToken;
    this.APIKey = APIKey;
    this.APISecret = APISecret;
  
    this.req                  = req;
    this.res                  = res;
  
    this.MIXPANEL_COOKIE_NAME = 'mp_' + (this.APIToken || globalAPIToken)  + '_mixpanel';
  
    if (this.req)
      this.COOKIE_OPTIONS = {
          secure    : false
        , httpOnly  : false
        , expires   : new Date(Date.now() + 365 * 24 * 60 * 60 * 1000)
        , domain    : '.' + this.req.headers.host.split('.').slice(-2).join('.')
      };
  
    this.cookieJar  = this.req && this.res 
                        ? new cookies(req, res) 
                        : undefined
                        ;
  
    this.superProperties  = this.cookieJar && this.cookieJar.get(this.MIXPANEL_COOKIE_NAME) 
                              ? JSON.parse(decodeURIComponent(this.cookieJar.get(this.MIXPANEL_COOKIE_NAME))) 
                              : {}
                              ;
  
    this.people = new MixpanelPeople(this);
  }