refactor: format topExamples code and add execExample.

[soarpenguin]

Ⅰ. Describe what this PR did

refactor: format topExamples code and add execExample.

Ⅱ. Does this pull request fix one issue?

Ⅲ. Describe how you did it

Ⅳ. Describe how to verify it

Ⅴ. Special notes for reviews

[pouchrobot]

@soarpenguin Thanks for your contribution. 🍻
Please sign off in each of your commits.

[pouchrobot]

We found this is your first time to contribute to Pouch, @soarpenguin
👏 We really appreciate it.
Just remind that you have read the contribution guide: https://github.com/alibaba/pouch/blob/master/CONTRIBUTING.md
If you didn't, you should do that first. If done, welcome again and please enjoy hacking! 🍻

[allencloud]

LGTM, thanks a lot for your work. I will merge this until the readiness of CI. 🥂

[codecov-io]

Codecov Report

Merging #1319 into master will decrease coverage by <.01%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #1319      +/-   ##
==========================================
- Coverage   17.39%   17.39%   -0.01%     
==========================================
  Files         189      189              
  Lines       11772    11776       +4     
==========================================
  Hits         2048     2048              
- Misses       9576     9580       +4     
  Partials      148      148

Impacted Files	Coverage Δ
cli/top.go	0% <0%> (ø)	⬆️
cli/exec.go	0% <0%> (ø)	⬆️
cri/src/cri_utils.go
cri/src/cri_network.go
cri/src/cri.go
cri/src/cri_types.go
cri/src/cri_wrapper.go
cri/src/cri_stream.go
daemon/mgr/cri.go	0% <0%> (ø)
daemon/mgr/cri_network.go	0% <0%> (ø)
... and 4 more