docs: @SuppressWarnings("unused")
      private void close() {
          try {
              if (LOGGER.isTraceEnabled()) {
                  LOGGER.trace("Doing client selector close");
              }
              selector.close();
              if (LOGGER.isTraceEnabled()) {
                  LOGGER.trace("Closed client selector");
              }
          } catch (IOException e) {
              LOGGER.warn("Ignoring exception during selector close", e);
          }
      }