Future Optmizations

[Kiyoshika]

When first writing this library I didn't want to prematurely optimize (and still don't care about it just yet) but wanted to store any future possible optimizations whenever we get to that point.

• fetch_..._string() in json_internal
  • These functions reallocate and free different heap buffers many times (especially for large files). Will probably be worth it to use ONE heap buffer during parsing and just resize it if we end up getting a value that's larger than the current max
  • This also computes the length of the parse string each time (which sometimes can be very long). Will be better to precompute it and pass it as an arg or store it in parse_info