ENH: fix cudf comp issue

[luweizheng]

fix cudf comp issue:

• buffer: buffer._owner, size, _offset
• cudf and pandas work differently on merge

[qinxuye]

LGTM

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 80.97%. Comparing base (3be13c7) to head (beadf54).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #803      +/-   ##
==========================================
+ Coverage   80.70%   80.97%   +0.27%     
==========================================
  Files        1070     1070              
  Lines       80015    80015              
  Branches    16522    16522              
==========================================
+ Hits        64574    64792     +218     
+ Misses      13881    13647     -234     
- Partials     1560     1576      +16     

Flag	Coverage Δ
unittests	80.92% <ø> (+0.27%)	⬆️

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