optimization thoughts

[ctb]

A miscellaneous collection of thoughts that are not big enough or well enough formed to put in their own issues, but should be noted somewhere.

We may be double-hashing things - hashing the hash vals. Can we use murmurhash as the hashing approach?

What kind of perf benchmarking can we do? codspeed looked pretty nice when used over in sourmash.

We should use String less and &str more. References over clones, etc.

Similarly, there are a few places where we are using vec unnecessarily, I think.

[ctb]

note: we can use &str not String: https://stackoverflow.com/questions/60512888/how-is-memory-managed-with-str-and-string-native-types-and-pyresultt-when-pa

[Adamtaranto]

Low hanging efficiency fruit:

• Revcomp the full seq and step through backwards in sliding window to find canonical kmers instead of revcomp per kmer.
• Make consume multithreaded at the kmer level - both KmersAndHashesIter and SeqToHashes are iterators so this should be fairly simple, unless we are worried about diff threads trying to write to same hash?
• Make multithreaded at the sequence level?
• Consume directly from file to avoid having to load seqs in Python and pass back to rust per WIP: add consume_file #10

Originally posted by @Adamtaranto in #70 (comment)