code: @Override
      public void handleChannelData(final String action, final JSONArray payload) throws BitfinexClientException {
          logger.debug("Got notification callback {}", payload.toString());
  
          if (payload.isEmpty()) {
              return;
          }
  
          // Test for order error callback
          // [0,"n",[null,"on-req",null,null,[null,null,1513970684865000,"tBTCUSD",null,null,0.001,0.001,"EXCHANGE MARKET",null,null,null,null,null,null,null,12940,null,null,null,null,null,null,0,null,null],null,"ERROR","Invalid order: minimum size for BTC/USD is 0.002"]]
          if ("on-req".equals(payload.getString(1))) {
              final String state = payload.optString(6);
              if ("ERROR".equals(state)) {
                  BitfinexSubmittedOrder exchangeOrder = jsonToBitfinexSubmittedOrder(payload);
                  submittedOrderConsumer.accept(symbol, exchangeOrder);
              }
          }
      }
docs: {@inheritDoc}