Add benchmarks for performance tuning

[neoeinstein]

• [x] Decide on a benchmarking library that works well with xUnit
  • xunit.benchmark
  • NBench
  • xunit.performance
  • BenchmarkDotNet
• [ ] Develop a few representative schemas along with Chiron encoders/decoders
  • Serialize/Deserialize
  • Small records with one or two fields.
  • Large records
  • Parse/Format
  • Trivial
  • Large strings
  • Object with many properties
  • Deeply nested objects/arrays
  • Different parsing/formatting strategies
• [ ] Determine metrics by which to determine improvement

[neoeinstein]

I'm leaning toward NBench at the moment. It requires an external runner, so it doesn't integrate directly with xUnit. Nonetheless, it seems to have some nice features, including memory and GC benchmarking. It's not quite idiomatic F#, though, so each benchmark needs to be implemented with an OO type. I've posted the work-in-progress into the add-benchmarks branch.

[neoeinstein]

After more exploration, I've found BenchmarkDotNet which seems to be becoming the preferred benchmark tool. It works well integrated as part of an executable and allows for doing A/B testing.

[kolektiv]

I like BenchmarkDotNet, I've had nice experiences with it elsewhere. More than happy for that to be the story for Chiron!