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/bottlerocket/sources/api/early-boot-config
    
    the code of the file until where you have to start completion: use bottlerocket_variant::{Variant, VARIANT_ENV};

fn main() {
    let variant = match Variant::from_env() {
        Ok(variant) => variant,
        Err(e) => {
            eprintln!(
                "For local builds, you must set the '{}' environment variable so we know \
                which data provider to build. Valid values are the directories in \
                models/src/variants/, for example 'aws-ecs-1': {}",
                VARIANT_ENV, e,
            );
 
    
fn main() {
    let variant = match Variant::from_env() {
        Ok(variant) => variant,
        Err(e) => {
            eprintln!(
                "For local builds, you must set the '{}' environment variable so we know \
                which data provider to build. Valid values are the directories in \
                models/src/variants/, for example 'aws-ecs-1': {}",
                VARIANT_ENV, e,
            );
            std::process::exit(1);
        }
    };
    variant.emit_cfgs();

    generate_readme::from_main().unwrap();
}