Avoid hasattr in hot loop in brotli decoder

[auscompgeek]

hasattr has a nasty performance penalty when it returns false: in the background it is actually a try/except AttributeError. Since we know the method we want won't change, by instead caching the bound method object we can amortise the cost across an entire encoded body.

This removes the intermediate decompress method altogether, instead giving the underlying method the decompress name.

[codecov]

Codecov Report

Merging #1858 into master will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master     #1858   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           22        22           
  Lines         2013      2012    -1     
=========================================
- Hits          2013      2012    -1     

Flag	Coverage Δ
#unittests	99.60% <50.00%> (-0.01%)	⬇️

Impacted Files	Coverage Δ
src/urllib3/response.py	100.00% <100.00%> (ø)

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[pquentin]

Thanks!

While the change makes sense, can you please share the speed improvement you're seeing?

[auscompgeek]

I haven't had a chance to actually benchmark this yet. I might get an opportunity to do so later this week, but no guarantees.

[sethmlarson]

LGTM, thank you! Would still like to see the performance difference if possible.