Consider performance improvements for Date/Time parsing

Jsoniter project (https://github.com/plokhotnyuk/jsoniter-scala) has many impressive performance optimizations; linked f.ex from here:

https://www.reddit.com/r/java/comments/darehu/jackson_release_210/f1ysf1e/

and ones relevant to this repo have to with Java 8 date/time type decoding.
It would be great to investigate if some of the techniques could be used here: handling of Date/Time values is notoriously CPU intensive (although not necessarily low-level encoding/decoding?).