PERF: to_set speeds up especial to large data

[Zeroto521]

• closes PERF: to_set speeds up especial for large data #542
• whatsnew entry

Apply to index accessor

[codecov]

Codecov Report

Merging #543 (3e4ba6b) into main (775b41e) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #543   +/-   ##
=======================================
  Coverage   99.63%   99.63%           
=======================================
  Files          59       59           
  Lines         816      816           
  Branches       89       89           
=======================================
  Hits          813      813           
  Misses          1        1           
  Partials        2        2           

Impacted Files	Coverage Δ
dtoolkit/accessor/index/to_set.py	100.00% <100.00%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 775b41e...3e4ba6b. Read the comment docs.