This mod uses Mixins instead of registry replacement for a more mod friendly, less invasive way of optimizing the furnace that can also be done server only.
For more detailed info read the spoiler below.
Now what you might be wondering is why release this at all then?
Doesn't Forge already have this mod?
Well yes, you would be correct, however, it has one major flaw: registry replacement.
In essence, what registry replacement does is allow a modder to replace any block/item/fluid, etc... in the game and subsitute it with their own subclass.
However, there's a few catches.
1) Only one mod in a pack can registry replace per pack, if more than one mod attempts to registry replace the same block, the other overrides will be discarded.
2) All references to the old object become invalid and can lead to bad behavior such as breaking other mods or even vanilla itself (try registry replacing stone, I dare you.)
3) All mixins, coremods, etc will not get called if the subclass overrides those methods and doesn't call super (why blast processing won't work with normal fast furnace, as it replaces the tick function of the vanilla furnace so my own mixins won't apply)
The advantages of the mixin version vs the registry replacement version is:
1) it doesn't use registry replacement so it will work fine with other mods that modify the furnace.
2) Because it doesn't modify registries, it can be ran serverside only as processing only happens on the (logical) server (yes, the mod still works in singleplayer).
3) No methods are overridden so it will work with other mods injecting into the same method.
Mineuniverse