code: function findAvailablePort(port = 9528) {
      return new Promise((resolve, reject) => {
          const check = () => {
              portIsOccupied(port, (isFound) => {
                  if (isFound) {
                      resolve(port);
                  } else {
                      port++;
  
                      if (port > 65535) {
                          reject();
                      } else {
                          check();
                      }
                  }
              });
          };
  
          check();
      });
  }
docs: 找到当前未被占用的端口号
  
  @param {Number} [port] 查找的起始端口号
  @return {Promise}