Add PreChunk and PreVacant

[tkf]

No description provided.

[codecov]

Codecov Report

❌ Patch coverage is 89.65517% with 6 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.37%. Comparing base (eb6f73a) to head (ddeedb6).
⚠️ Report is 94 commits behind head on master.

Files with missing lines	Patch %	Lines
src/splitby.jl	89.65%	6 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #464      +/-   ##
==========================================
- Coverage   91.41%   91.37%   -0.04%     
==========================================
  Files          32       32              
  Lines        2120     2157      +37     
==========================================
+ Hits         1938     1971      +33     
- Misses        182      186       +4     

Flag	Coverage Δ
unittests	91.37% <89.65%> (-0.04%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.