How do I set a block in a specific location in every chunk with the new world gen features

In the project I am working on I am required to be able to place blocks in specific locations in every chunk. Lets say for example, place a bedrock at y=100 for each chunk. This was very easy with IWorldGenerator, in fact I can give a pseudocode example right now:

//just pseudocode but you get the point
class Whatever implements IWorldGenerator
{

	@Override
	generate
	{
		setblock(chunkX,100,chunkZ,bedrock)
		
	}

}

class SomeProxy
{
	add registry thing (Whatever)
}

there is very little documentation I can find on the new way world generation works, but worst of all the only examples I can find just use built in ore features or decoration features or whatnot. How can I do this in recent versions?