code: @Override
      public void hello(Hello hello) {
          log.info("Received hello from connection: {}", connection);
          connection.send(new Hello(WireCommands.WIRE_VERSION, WireCommands.OLDEST_COMPATIBLE_VERSION));
          if (hello.getLowVersion() > WireCommands.WIRE_VERSION || hello.getHighVersion() < WireCommands.OLDEST_COMPATIBLE_VERSION) {
              log.warn("Incompatible wire protocol versions {} from connection {}", hello, connection);
              connection.close();
          }
      }
docs: region RequestProcessor Implementation