code: public com.google.protobuf.ByteString
        getRefererBytes() {
      java.lang.Object ref = referer_;
      if (ref instanceof java.lang.String) {
        com.google.protobuf.ByteString b = 
            com.google.protobuf.ByteString.copyFromUtf8(
                (java.lang.String) ref);
        referer_ = b;
        return b;
      } else {
        return (com.google.protobuf.ByteString) ref;
      }
    }
docs: <pre>
  The referer URL of the request, as defined in
  [HTTP/1.1 Header Field Definitions](http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html).
  </pre>
  
  <code>string referer = 8;</code>