Release v2.0.0-preview.4

What's Changed

• Refactor out various duplicated code throughout the codebase into their own nice neat little packages by @toptobes in #99
• Serdes fuzz testing and some bug fixes/compatability work by @toptobes in #100
• Small backlog of changes by @toptobes in #102

Full Changelog: v2.0.0-preview.3...v2.0.0-preview.4