@Override
 public long arrivalTimeNanos() {
   return delegate.arrivalTimeNanos();
 }
 @Override
 public ServerInfo serverInfo() {
   return delegate.serverInfo();
 }
 @Override
 public boolean isExpired() {
   return delegate.isExpired();
 }
 @Override
 public void drop() {
   delegate.drop();
 }
 @Override
 public void reply(Response<ByteString> response) {
   delegate.reply(response);
 }
 @Override
 public Request request() {
   return delegate.request();
 }