pysimdjson

This is the main bottleneck in pysimdjson[1]. 95-99%[2] of the time is spent creating Python objects rather than parsing the documents. There was no trick I could find (although treating all strings as bytes instead of using PyUnicode_DecodeUTF8/unicode_decode_utf8 was a fairly large gain on string-heavy documents) to reduce the cost of bringing the document into Python land, so I added a quick hack to push the filtering down into C, since most of my use cases only need a small part of the full document. [1]: https://github.com/TkTech/pysimdjson [2]: https://github.com/TkTech/pysimdjson/issues/22