code: function(name, value) {
      var header = { raw: value };
  
      name = Utils.headerize(name);
  
      if(this.headers[name]) {
        this.headers[name].push(header);
      } else {
        this.headers[name] = [header];
      }
    }
docs: Insert a header of the given name and value into the last position of the
  header array.