General performance improvements. Identify hotspots via profiling. Attempt to improve by optimizing loops, minimizing allocations, etc.
I came up with a couple of small tweaks:
The changes are minor, and only amount to 1-2% improvements (depends on workload), but worth making.
The PR also contains some unrelated changes removing dead code and refactoring tests.
There is actual cython optimization work going on here: https://github.com/datastax/python-driver/compare/master...markflorisson:cython