Custom packets for ItemExchange trade displays

[Protonull]

This allows for mods like TradeX to more accurately track shop chests and their offerings.

[okx-code]

Hey gson is thread safe (mentioned in the navadocs) so you don't need to synchronise on it

[okx-code]

Also with the namespacedkey I feel like it's a lot of complexity to handle this memoisation, is there a way to reduce it? Perhaps hardcoding the plugin name or dependency injecting it.

[Protonull]

Also with the namespacedkey I feel like it's a lot of complexity to handle this memoisation, is there a way to reduce it?

It's probably just class-loading neurosis on my part, but I fret over these kinds of static fields which are set upon class initialisation, which could potentially happen prior to ItemExchangePlugin's constructor being called and its instance field set. I'm probably fretting over nothing.