fix: add chanx

[LaurenceLiZhixin]

What this PR does:

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[codecov-commenter]

Codecov Report

Merging #63 (f5ac0e1) into master (c144977) will increase coverage by 0.29%.
The diff coverage is 87.87%.

@@            Coverage Diff             @@
##           master      #63      +/-   ##
==========================================
+ Coverage   74.40%   74.69%   +0.29%     
==========================================
  Files          35       37       +2     
  Lines        3797     3896      +99     
==========================================
+ Hits         2825     2910      +85     
- Misses        800      809       +9     
- Partials      172      177       +5     

Impacted Files	Coverage Δ
chanx/ringbuffer.go	87.09% <87.09%> (ø)
chanx/unbounded_chan.go	89.18% <89.18%> (ø)
time/timer.go	77.15% <0.00%> (-0.67%)	⬇️

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