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: riscv.rs
    path of file: ./repos/oreboot/xtask/src/qemu
    
    the code of the file until where you have to start completion: use crate::util::{
    compile_board_dt, dis
    
fn xtask_concat_flash_binaries(env: &Env) {
    let dist_dir = dist_dir(env, TARGET);
    let mut main_file = File::options()
        .read(true)
        .open(dist_dir.join(MAIN_BIN))
        .expect("open main binary file");

    let output_file_path = dist_dir.join(IMAGE_BIN);
    let mut output_file = File::options()
        .write(true)
        .create(true)
        .open(&output_file_path)
        .expect("create output binary file");

    output_file.set_len(SRAM0_SIZE).unwrap(); // FIXME: depend on storage
    io::copy(&mut main_file, &mut output_file).expect("copy main binary");

    println!("======= DONE =======");
    println!("Output file: {:?}", &output_file_path.into_os_string());
}