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: drunkard.rs
    path of file: ./repos/bevy_roguelike/map_generator/src
    
    the code of the file until where you have to start completion: use super::prelude::*;

const DEFAULT_WALK_RATIO: f32 = 0.015;
const DEFAULT_FLOOR_RATIO: f32 = 0.6;

pub struct DrunkardGenerator {
    pub walk_ratio: f32,
    pub floor_ratio: f32,
}

impl Default for DrunkardGenerator {
    fn default() -> Self {
        Self {
            walk_ratio: DEFAULT_WALK_RATIO,
            floor_ratio: DEFAULT_FLOOR_RATIO,
        }
    }
}

impl MapGenerator for DrunkardGenerator {
    fn gen(&self, rng: &mut StdRng, size: IVec2) -> Map {
        let mut map = Map::filled_with(size, Tile::Wall);
        let mut room_centers = 
    
    fn gen(&self, rng: &mut StdRng, size: IVec2) -> Map {
        let mut map = Map::filled_with(size, Tile::Wall);
        let mut room_centers = Vec::new();
        let walk_steps = ((size.x * size.y) as f32 * self.walk_ratio) as usize;
        let desired_floor = ((size.x * size.y) as f32 * self.floor_ratio) as usize;

        while map.iter().filter(|t| **t == Tile::Floor).count() < desired_floor {
            let mut from = IVec2::new(
                rng.gen_range(1..map.size().x - 1),
                rng.gen_range(1..map.size().y - 1),
            );
            room_centers.push(from);
            let stagger_count = usize::max(walk_steps / 10, 5);
            for _ in 0..stagger_count {
                from = walk(from, walk_steps, rng, &mut map);
            }
        }

        map
    }