The frequent invocation of time_sync() can result in IOErrors

[kwseeker]

Perhaps ntp.aliyun.com has imposed limitations on the frequency of access.
Error message:
called Result::unwrap() on an Err value: IOError(Os { code: 11, kind: WouldBlock, message: "Resource temporarily unavailable" })

[blueokanna]

It may requested so fast that try decrease req times may fix it. I will optimised that problem which add local time to check in order to helping you to slove it. Thank you!