@Override protected void doEnqueue(final Callback<V> callback) {
      delegate.enqueue(new Callback<V>() {
        @Override public void onSuccess(V value) {
          callback.onSuccess(value);
        }

        @Override public void onError(Throwable t) {
          errorHandler.onErrorReturn(t, callback);
        }
      });
    }
Returns a copy of this object, so you can make an identical follow-up request.
zipkin/src/main/java/zipkin2/Call.java