Add Benchmarks

We should definitely add benchmarks for important functionality; this will help us improve performance over time and be sensitive to performance regressions.

Some help on this would be great; even if you only add one or two benchmarks :)

The issue names no files, tests, benchmark framework, or specific functionality. Start by locating the project's existing test and build setup, then identify which functionality maintainers consider important. Done means adding one or two useful benchmarks that can be rerun to detect performance regressions.

Written by the indexing model from the issue text.