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: build.rs
    path of file: ./repos/orbtk/utils
    
    the code of the file until where you have to start completion: use std::env;
use std::error::Error;
use std::fs::File;
use std::io::{BufRead, BufReader, BufWriter, Write};
use std::path::{Path, PathBuf};

fn main() -> Result<(), Box<dyn Error>> {
    println!("cargo:rerun-if-changed=colors.txt");
    let path = Path::new(&env::var("OUT_DIR").unwrap()).join("colors.rs");
    let mut file = BufWriter::new(File::create(&path).unwrap());

    let rdr = BufReader::new(File::open(
        PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap()).join("colors.txt"),
    )?);

    let mut map = 
    
fn main() -> Result<(), Box<dyn Error>> {
    println!("cargo:rerun-if-changed=colors.txt");
    let path = Path::new(&env::var("OUT_DIR").unwrap()).join("colors.rs");
    let mut file = BufWriter::new(File::create(&path).unwrap());

    let rdr = BufReader::new(File::open(
        PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap()).join("colors.txt"),
    )?);

    let mut map = phf_codegen::Map::new();
    let mut recs: Vec<(String, String)> = Vec::new();

    for result in rdr.lines() {
        let record = result?;
        let record = record.split("//").next().unwrap().trim();
        if record.is_empty() {
            continue;
        }
        let mut record = record.split_whitespace();
        let id = record.next().unwrap().to_owned();
        let hex = record.next().unwrap().to_owned();
        let clean_hex = hex.trim_start_matches('#');
        let color = match clean_hex.len() {
            3 => {
                let d = u32::from_str_radix(clean_hex, 16).unwrap_or(0);

                let mut r = (d & 0xF) << 4;
                let mut g = ((d >> 4) & 0xF) << 4;
                let mut b = ((d >> 8) & 0xF) << 4;
                r |= r >> 4;
                g |= g >> 4;
                b |= b >> 4;

                format!("Color::rgb({}, {}, {})", r, g, b)
            }
            6 => {
                let x = u32::from_str_radix(clean_hex, 16).unwrap_or(0);

                format!(
                    "Color::rgb({}, {}, {})",
                    ((x >> 16) & 0xFF) as u8,
                    ((x >> 8) & 0xFF) as u8,
                    (x & 0xFF) as u8
                )
            }
            _ => panic!(""),
        };
        recs.push((id, color));
    }

    for rec in recs.iter() {
        map.entry(&*rec.0, &rec.1);
    }

    map.entry("transparent", "Color::rgba(0, 0, 0, 0)");

    writeln!(
        &mut file,
        "static COLORS: phf::Map<&'static str, Color> = \n{};\n",
        map.build()
    )
    .unwrap();

    Ok(())
}