You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: mod.rs
    path of file: ./repos/rustrogueliketutorial/chapter-75-darkplaza/src/map_builders/prefab_builder
    
    the code of the file until where you have to start completion: use super::{InitialMapBuilder, MetaMapBuilder, BuilderMap, TileType, Position};
pub mod prefab_levels;
pub mod prefab_sections;
pub mod prefab_rooms;
use std::collections::HashSet;

#[derive(PartialEq, Copy, Clone)]
#[allow(dead_code)]
pub enum PrefabMode {
    RexLevel{ template : &'static str },
    Constant{ level : prefab_levels::PrefabLevel },
    Sectional{ section : prefab_sections::PrefabSection },
    RoomVaults
}

#[allow(dead_code)]
pub struct PrefabBuilder {
    mode: PrefabMode
}

impl MetaMapBuilder for PrefabBuilder {
    fn build_map(&mut self, build_data : &mut BuilderMap)  {
        self.build(build_data);
    }
}

impl InitialMapBuilder for PrefabBuilder {
    #[all
    
    fn load_rex_map(&mut self, path: &str, build_data : &mut BuilderMap) {
        let xp_file = rltk::rex::XpFile::from_resource(path).unwrap();

        for layer in &xp_file.layers {
            for y in 0..layer.height {
                for x in 0..layer.width {
                    let cell = layer.get(x, y).unwrap();
                    if x < build_data.map.width as usize && y < build_data.map.height as usize {
                        let idx = build_data.map.xy_idx(x as i32, y as i32);
                        // We're doing some nasty casting to make it easier to type things like '#' in the match
                        self.char_to_map(cell.ch as u8 as char, idx, build_data);
                    }
                }
            }
        }
    }