Remove unused from datetime.pxd, check for fastpath in ensure_datetime64ns

[jbrockmendel]

Still a hodgepodge, but a somewhat smaller hodgepodge.

[jbrockmendel]

Same geopandas error. Looks like its showing up in a couple of PRs (although a couple also have problems I need to fix).

[codecov]

Codecov Report

Merging #18453 into master will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #18453      +/-   ##
==========================================
- Coverage   91.35%   91.34%   -0.02%     
==========================================
  Files         163      163              
  Lines       49695    49695              
==========================================
- Hits        45401    45392       -9     
- Misses       4294     4303       +9

Flag	Coverage Δ
#multiple	89.14% <ø> (ø)	⬆️
#single	39.66% <ø> (-0.07%)	⬇️

Impacted Files	Coverage Δ
pandas/io/gbq.py	25% <0%> (-58.34%)	⬇️
pandas/core/frame.py	97.8% <0%> (-0.1%)	⬇️

---

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 e6eac0b...6e391d8. Read the comment docs.

[codecov]

Codecov Report

Merging #18453 into master will decrease coverage by 0.04%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #18453      +/-   ##
==========================================
- Coverage   91.35%   91.31%   -0.05%     
==========================================
  Files         163      163              
  Lines       49695    49695              
==========================================
- Hits        45401    45380      -21     
- Misses       4294     4315      +21

Flag	Coverage Δ
#multiple	89.11% <ø> (-0.03%)	⬇️
#single	39.66% <ø> (-0.07%)	⬇️

Impacted Files	Coverage Δ
pandas/io/gbq.py	25% <0%> (-58.34%)	⬇️
pandas/plotting/_converter.py	63.44% <0%> (-1.82%)	⬇️
pandas/core/frame.py	97.8% <0%> (-0.1%)	⬇️

---

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 e6eac0b...6e391d8. Read the comment docs.

[jreback]

prob should just blow away src/datetime.pxd

[jbrockmendel]

prob should just blow away src/datetime.pxd

Definitely coming up, yah.