ARROW-11707: [Rust] support CSV schema inference without file IO

[houqp]

This patch set makes it possible for downstream application to do schema inference with IOs other than local filesystem.

[houqp]

this is a no op.

[alamb]

That is a good catch.

[github-actions]

https://issues.apache.org/jira/browse/ARROW-11707

[codecov-io]

Codecov Report

Merging #9534 (e3312f2) into master (35daca2) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #9534   +/-   ##
=======================================
  Coverage   82.32%   82.32%           
=======================================
  Files         245      245           
  Lines       56412    56414    +2     
=======================================
+ Hits        46442    46445    +3     
+ Misses       9970     9969    -1     

Impacted Files	Coverage Δ
rust/arrow/src/csv/reader.rs	93.17% <100.00%> (+0.02%)	⬆️
rust/parquet/src/encodings/encoding.rs	95.05% <0.00%> (+0.19%)	⬆️

---

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 35daca2...e3312f2. Read the comment docs.

[alamb]

Looks good to me -- thanks @houqp

[alamb]

That is a good catch.

[alamb]

@houqp / @nevi-me is this PR ready to go? It looks good to me. I'll plan to merge it tomorrow if I don't hear anything otherwise

[nevi-me]

@houqp / @nevi-me is this PR ready to go? It looks good to me. I'll plan to merge it tomorrow if I don't hear anything otherwise

I was going to wait for #9534 (comment)

[alamb]

Makes sense @nevi-me -- sorry I was getting lost with the comment threads. Thank you

[houqp]

alright, pushed reader offset rewind fix.