fix: use array instead of Vec for Codon representation (and other free perf improvements)

[tedil]

• use [u8; 3] instead of Vec, i.e. stack vs heap
• use ahash instead of fxhash
• use array slicing &c[..3] instead of iter().take(3) (even though that should not really have made a difference, but according to criterion, seemed to be the case)
• make translate a little more readable with or_else chaining

[codecov]

Codecov Report

Attention: Patch coverage is 83.33333% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 87.42%. Comparing base (721d606) to head (2b08951).

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #169      +/-   ##
==========================================
- Coverage   87.42%   87.42%   -0.01%     
==========================================
  Files          18       18              
  Lines        7700     7705       +5     
==========================================
+ Hits         6732     6736       +4     
- Misses        968      969       +1     

Files	Coverage Δ
src/sequences.rs	98.28% <83.33%> (-0.11%)	⬇️

[xiamaz]

Thanks a lot. This generally looks good. How much performance impact are you seeing in a test case?

[tedil]

main branch

     Running benches/translate_cds.rs (target/release/deps/translate_cds-c57b7f59d5053bc8)
translate_cds TTN       time:   [153.05 µs 153.31 µs 153.61 µs]
Found 14 outliers among 100 measurements (14.00%)
  5 (5.00%) high mild
  9 (9.00%) high severe

perf-codon-repr branch

     Running benches/translate_cds.rs (target/release/deps/translate_cds-41f293dcbeaaadcb)
translate_cds TTN       time:   [120.43 µs 121.08 µs 121.87 µs]
                        change: [-20.521% -19.639% -18.312%] (p = 0.00 < 0.05)
                        Performance has improved.
Found 11 outliers among 100 measurements (11.00%)
  3 (3.00%) high mild
  8 (8.00%) high severe