code: function listen(port, cb) {
      return new Promise((resolve, reject) => {
          let completed = ssocket_helpers.createSimplePromiseCompletedAction(resolve, reject);
          try {
              let serverToClient;
              let server = Net.createServer((connectionWithClient) => {
                  try {
                      if (cb) {
                          cb(null, createServer(connectionWithClient));
                      }
                  }
                  catch (e) {
                      if (cb) {
                          cb(e);
                      }
                  }
              });
              let isListening = false;
              server.once('error', (err) => {
                  if (!isListening && err) {
                      completed(err);
                  }
              });
              server.on('listening', () => {
                  isListening = true;
                  completed(null, server);
              });
              server.listen(port);
          }
          catch (e) {
              completed(e);
          }
      });
  }
docs: Starts listening on a port.
  
  @param {number} port The TCP port to listen on.
  @param {ListenCallback} cb The listener callback.
  
  @return {Promise<Net.Server>} The promise.