code: public Closeable onMyTradeEvent(final BiConsumer<BitfinexAccountSymbol, BitfinexMyExecutedTrade> listener) {
          tradeConsumers.offer(listener);
          return () -> tradeConsumers.remove(listener);
      }
docs: registers listener for user account related events - executed trades (against submitted order) events
  @param listener of event
  @return hook of this listener