docs: function StatelessEmitter(ptcl, writableFactory, opts) {
    MessageEmitter.call(this, ptcl, opts);
    this._writableFactory = writableFactory;
  
    if (!opts || !opts.noPing) {
      // Ping the server to check whether the remote protocol is compatible.
      this.emitMessage('', {}, function (err) {
        if (err) {
          this.emit('error', err);
        }
      });
    }
  }