MAINT: Buttress memory handling in C csv engine
Title is self-explanatory.

Follow-up to #16663.

# [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16673?src=pr&el=h1) Report
> Merging [#16673](https://codecov.io/gh/pandas-dev/pandas/pull/16673?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/0281886fbdf0d1837c2af08af15949c1d98bf612?src=pr&el=desc) will **increase** coverage by `0.02%`.
> The diff coverage is `n/a`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/16673/graphs/tree.svg?height=150&token=eZ4WkYLtcO&src=pr&width=650)](https://codecov.io/gh/pandas-dev/pandas/pull/16673?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #16673      +/-   ##
==========================================
+ Coverage   90.92%   90.95%   +0.02%     
==========================================
  Files         161      161              
  Lines       49272    49272              
==========================================
+ Hits        44803    44815      +12     
+ Misses       4469     4457      -12
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `88.71% <ø> (+0.02%)` | :arrow_up: |
| #single | `40.22% <ø> (ø)` | :arrow_up: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/16673?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/16673?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `65.05% <0%> (+1.81%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16673?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/16673?src=pr&el=footer). Last update [0281886...86c5b9a](https://codecov.io/gh/pandas-dev/pandas/pull/16673?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 @jreback : If #16675 works, then I'll close this PR in favor of that one. Yep, #16675 is working.  Closing this PR.