docs: public void connect(String group, Address addr, String logical_name, PhysicalAddress phys_addr) throws Exception {
          synchronized(this) {
              _doConnect();
          }
          try {
              writeRequest(new GossipData(GossipType.REGISTER, group, addr, logical_name, phys_addr));
          }
          catch(Exception ex) {
              throw new Exception(String.format("connection to %s failed: %s", group, ex));
          }
      }