BUG: GH29461 Strftime
State: closed

- [x] closes #29461 
- [x] tests added / passed
- [x] passes `black pandas`
- [x] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [x] whatsnew entry

Closed the other PR while I sorted some things out. 

Labels:
name: Datetime
description: Datetime data dtype
name: Output-Formatting
description: __repr__ of pandas objects, to_string

Comments:
@matteosantama can you merge master and fix the conflicts?
can u merge master, and show benchmarks again; ping on green
@jreback All checks passing. ASV output is a little confusing. Not entirely sure why so many tests were affected.

```
       before           after         ratio
     [bfac1362]       [b0de2c4c]
     <master>         <strftime>
+      6.44±0.4μs        34.8±30μs     5.41  tslibs.timestamp.TimestampProperties.time_is_month_end(tzfile('/usr/share/zoneinfo/US/Central'), 'B')
+         204±4ns       1.06±0.8μs     5.18  tslibs.timestamp.TimestampProperties.time_microsecond(tzlocal(), 'B')
+      8.78±0.3μs        42.3±30μs     4.81  tslibs.timestamp.TimestampProperties.time_month_name(<DstTzInfo 'Europe/Amsterdam' LMT+0:20:00 STD>, None)
+      7.77±0.2μs        19.6±10μs     2.53  tslibs.timestamp.TimestampProperties.time_month_name(<UTC>, 'B')
+      3.52±0.1μs       4.24±0.1μs     1.20  tslibs.timestamp.TimestampStrftimeMethod.time_strftime('%Y-%m-%d %H:%M:%S.%f')
+     3.16±0.06μs       3.60±0.1μs     1.14  tslibs.timestamp.TimestampStrftimeMethod.time_strftime('%Y-%m-%d %H:%M:%S')
-        314±10ns          284±3ns     0.90  tslibs.timestamp.TimestampProperties.time_week(<DstTzInfo 'Europe/Amsterdam' LMT+0:20:00 STD>, None)
-         277±5ns          250±9ns     0.90  tslibs.timestamp.TimestampProperties.time_days_in_month(<UTC>, None)
-        279±20ns          251±5ns     0.90  tslibs.timestamp.TimestampProperties.time_days_in_month(datetime.timezone(datetime.timedelta(seconds=3600)), 'B')
-        320±20ns          284±2ns     0.89  tslibs.timestamp.TimestampProperties.time_week(tzlocal(), None)
-        279±40ns          248±4ns     0.89  tslibs.timestamp.TimestampProperties.time_is_year_start(tzlocal(), None)
-        283±10ns          250±4ns     0.88  tslibs.timestamp.TimestampProperties.time_dayofweek(<UTC>, None)
-        137±10μs          120±2μs     0.88  tslibs.timestamp.TimestampOps.time_ceil(tzfile('/usr/share/zoneinfo/US/Central'))
-        548±10ns          475±4ns     0.87  tslibs.timestamp.TimestampProperties.time_freqstr(<DstTzInfo 'Europe/Amsterdam' LMT+0:20:00 STD>, None)
-        79.4±4μs       68.7±0.5μs     0.87  tslibs.timestamp.TimestampOps.time_ceil(<UTC>)
-        227±30ns          195±7ns     0.86  tslibs.timestamp.TimestampProperties.time_microsecond(tzfile('/usr/share/zoneinfo/US/Central'), None)
-      9.13±0.9μs       7.51±0.1μs     0.82  tslibs.timestamp.TimestampConstruction.time_parse_iso8601_tz
-       81.3±20μs       52.9±0.9μs     0.65  tslibs.timestamp.TimestampOps.time_replace_tz(tzlocal())
-        18.1±5μs       11.5±0.3μs     0.63  tslibs.timestamp.TimestampOps.time_to_julian_date(tzutc())
-       43.8±20μs       25.5±0.5μs     0.58  tslibs.timestamp.TimestampOps.time_replace_tz(tzfile('/usr/share/zoneinfo/US/Central'))
-        20.9±7μs       11.5±0.3μs     0.55  tslibs.timestamp.TimestampOps.time_to_julian_date(None)
-       70.4±60μs       31.1±0.5μs     0.44  tslibs.timestamp.TimestampOps.time_replace_None(tzlocal())
-        5.45±5μs      2.28±0.06μs     0.42  tslibs.timestamp.TimestampOps.time_replace_None(tzutc())
-       539±300ns          219±4ns     0.41  tslibs.timestamp.TimestampProperties.time_is_quarter_start(tzfile('/usr/share/zoneinfo/US/Central'), None)
-        15.8±8μs       6.10±0.1μs     0.39  tslibs.timestamp.TimestampProperties.time_is_year_start(tzutc(), 'B')
-        15.2±8μs      5.82±0.08μs     0.38  tslibs.timestamp.TimestampProperties.time_is_month_start(None, 'B')
-        9.42±5μs       3.60±0.1μs     0.38  tslibs.timestamp.TimestampOps.time_normalize(None)
-       52.7±30μs       20.1±0.7μs     0.38  tslibs.timestamp.TimestampOps.time_replace_tz(<UTC>)
-       575±300ns          214±8ns     0.37  tslibs.timestamp.TimestampProperties.time_is_month_start(<DstTzInfo 'Europe/Amsterdam' LMT+0:20:00 STD>, None)
-        108±70μs       34.8±0.6μs     0.32  tslibs.timestamp.TimestampOps.time_normalize(<DstTzInfo 'Europe/Amsterdam' LMT+0:20:00 STD>)
-        7.23±5μs      2.33±0.05μs     0.32  tslibs.timestamp.TimestampOps.time_replace_None(<UTC>)
-       142±100μs       40.7±0.6μs     0.29  tslibs.timestamp.TimestampOps.time_normalize(tzlocal())
-       137±100μs         36.8±1μs     0.27  tslibs.timestamp.TimestampOps.time_normalize(tzfile('/usr/share/zoneinfo/US/Central'))
-       13.1±10μs      3.47±0.09μs     0.27  tslibs.timestamp.TimestampOps.time_normalize(<UTC>)
-        1.28±1μs          245±5ns     0.19  tslibs.timestamp.TimestampProperties.time_is_year_start(tzfile('/usr/share/zoneinfo/US/Central'), None)
-       647±500μs          123±1μs     0.19  tslibs.timestamp.TimestampOps.time_floor(tzfile('/usr/share/zoneinfo/US/Central'))
-      1.15±0.9μs          217±5ns     0.19  tslibs.timestamp.TimestampProperties.time_is_month_start(None, None)
-        2.54±2μs          476±3ns     0.19  tslibs.timestamp.TimestampProperties.time_freqstr(tzutc(), None)
-       362±300μs         67.5±2μs     0.19  tslibs.timestamp.TimestampOps.time_floor(<UTC>)
-        1.63±1μs          304±2ns     0.19  tslibs.timestamp.TimestampProperties.time_freqstr(datetime.timezone(datetime.timedelta(seconds=3600)), 'B')
-        1.33±1μs          248±3ns     0.19  tslibs.timestamp.TimestampProperties.time_is_year_start(<DstTzInfo 'Europe/Amsterdam' LMT+0:20:00 STD>, None)
-        1.29±1μs          240±3ns     0.19  tslibs.timestamp.TimestampOps.time_tz_localize(<UTC>)
-        1.64±1μs          305±6ns     0.19  tslibs.timestamp.TimestampProperties.time_freqstr(tzutc(), 'B')
-        1.28±1μs          236±4ns     0.18  tslibs.timestamp.TimestampProperties.time_dayofweek(None, 'B')
-        1.21±1μs          222±3ns     0.18  tslibs.timestamp.TimestampProperties.time_is_quarter_end(tzlocal(), None)
-        2.57±2μs          470±5ns     0.18  tslibs.timestamp.TimestampProperties.time_freqstr(tzlocal(), None)
-       859±700μs          154±4μs     0.18  tslibs.timestamp.TimestampOps.time_ceil(tzlocal())
-       668±500μs          119±1μs     0.18  tslibs.timestamp.TimestampOps.time_floor(<DstTzInfo 'Europe/Amsterdam' LMT+0:20:00 STD>)
-       386±300μs         67.0±2μs     0.17  tslibs.timestamp.TimestampOps.time_floor(tzutc())
-       564±500μs         91.5±2μs     0.16  tslibs.timestamp.TimestampOps.time_floor(datetime.timezone(datetime.timedelta(seconds=3600)))
-       945±900μs          149±3μs     0.16  tslibs.timestamp.TimestampOps.time_floor(tzlocal())
```
Hi @matteosantama  - is this still active? If so, could you address Jeff's and Will's comments please?