improve: adjust parent span's startTime when child span's startTime e…

[cindyliu-tec]

adjust parent span's startTime when child span's startTime early than it's parent span

[bboreham]

Thanks for the PR. Could you share a little how this situation comes up, why you care about it, etc.?

[cindyliu-tec]

Thanks for the PR. Could you share a little how this situation comes up, why you care about it, etc.?

I want it seem more like a normal request trace, a father span end when it's last child span end. if there still have child span being processing, but upper level span already ended, I think it looks weird. for example, when deployment-controller receive a mission to deploy a workload, people instinctively fell the mission only end when the workload is deployed successful or failed, instead of just assign tasks to replicaset-controller then itself end.