code: private CallbackResult<Boolean> renderBlock(BufferBuilder buffer, IBlockAccess world, BlockPos pos, IBlockState state)
  	{
  		IBlockRenderer renderer = getBlockRendererOverride(world, pos, state);
  		if (renderer == null)
  			renderer = blockRenderers.get(state.getBlock());
  		if (renderer == null)
  			return CallbackResult.noResult();
  
  		//convert pos to immutable one
  		return CallbackResult	.<Boolean> builder()
  								.value(renderer.renderBlock(buffer, world, new BlockPos(pos), state))
  								.withReturn(true)
  								.result();
  	}
docs: Renders a {@link IBlockState} with a registered {@link IBlockRenderer}.
  
  @param buffer the wr
  @param world the world
  @param pos the pos
  @param state the state
  @return true, if successful