How does server call client method in version 6.x ? about rpc-websockets HOT 4 CLOSED

const WebSocketServer = require('rpc-websockets').Server;

// instantiate Server and start listening for requests
const server = new WebSocketServer({
  port: 8082,
  host: '',
});

// register an RPC method
server.register('server_method', function(params) {
  return true;
});

const wsUri = 'ws://localhost:8082';
this.ws = new WebSocketClient(wsUri);
this.ws.registerMethod('client_method', () => {
  console.log('client_method call');
  return true;
});
this.ws.on('open', () => {
  this.ws.callMethod('server_method', [1]);
});