docs: public void close() throws IOException {
          if (LOG.isDebugEnabled()) {
              LOG.debug("Closing client for session: 0x"
                      + Long.toHexString(getSessionId()));
          }
  
          try {
              RequestHeader h = new RequestHeader();
              h.setType(ZooDefs.OpCode.closeSession);
  
              submitRequest(h, null, null, null);
          } catch (InterruptedException e) {
              // ignore, close the send/event threads
          } finally {
              disconnect();
          }
      }