code: private void bodyConsumerChunk(ByteBuf buffer) throws HandlerException {
      try {
        bodyConsumer.chunk(buffer, responder);
      } catch (Throwable t) {
        try {
          bodyConsumerError(t);
        } catch (Throwable t2) {
          exceptionHandler.handle(t2, request, responder);
          // log original throwable since we'll lose it otherwise
          LOG.debug("Handled exception thrown from handleError. original exception from chunk call was:", t);
          return;
        }
        exceptionHandler.handle(t, request, responder);
      }
    }
docs: Calls the {@link BodyConsumer#chunk(ByteBuf, HttpResponder)} method. If the chunk method call
  throws exception, the {@link BodyConsumer#handleError(Throwable)} will be called and this method will
  throw {@link HandlerException}.