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: get-root-ksks.rs
    path of file: ./repos/hickory-dns/util/src/bin
    
    the code of the file until where you have to start completion: // Copyright 2015-2017 Benjamin Fry <benjaminfry@me.com>
// Copyright 2017 Google LLC.
//
// Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or
// https://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
// https://opensource.org/licenses/MIT>, at your option. This file may not be
// copied, modified, or distributed except according to those terms.

//! The get_root_ksks program

// BINARY WARNINGS
#![warn(
    clippy::default_trait_access,
    clippy::dbg_macro,
    clippy::unimplemented,
    missing_copy_implementations,
    missing_docs,
    non_snake_case,
    non_upper_case_globals,
    rust_2018_idioms,
    unreachable_pub
)]

use std::fs::OpenOptions;
use std::io::Write;
use std::path::PathBuf;

use clap::{command, ArgMatches};

use hickory_proto::rr::dnssec::rdata::DNS
    
pub fn main() {
    hickory_util::logger(env!("CARGO_BIN_NAME"), Some(tracing::Level::INFO));

    let _matches = args();

    println!("querying for root key-signing-keys, ie dnskeys");
    let resolver = Resolver::default().expect("could not create resolver");
    let lookup = resolver
        .lookup(".", RecordType::DNSKEY)
        .expect("query failed");

    for r in lookup.iter() {
        #[allow(deprecated)]
        match r {
            RData::DNSSEC(DNSSECRData::DNSKEY(dnskey)) => {
                if !(dnskey.secure_entry_point() && dnskey.zone_key()) {
                    continue;
                }

                let key_tag = dnskey.calculate_key_tag().expect("key_tag failed");

                println!("found dnskey tag: {key_tag}");
                let extension = match dnskey.algorithm() {
                    Algorithm::RSASHA1
                    | Algorithm::RSASHA1NSEC3SHA1
                    | Algorithm::RSASHA256
                    | Algorithm::RSASHA512 => String::from("rsa"),
                    Algorithm::ECDSAP256SHA256 | Algorithm::ECDSAP384SHA384 => {
                        String::from("ecdsa")
                    }
                    Algorithm::ED25519 => String::from("ed25519"),
                    Algorithm::Unknown(v) => format!("unknown_{v}"),
                    alg => panic!("unknown Algorithm {:?}", alg),
                };

                let mut path = PathBuf::from("/tmp");
                path.push(format!("{key_tag}"));
                path.set_extension(extension);

                let mut file = OpenOptions::new();
                let mut file = file
                    .write(true)
                    .read(false)
                    .truncate(true)
                    .create(true)
                    .open(&path)
                    .expect("couldn't open file for writing");

                file.write_all(dnskey.public_key())
                    .expect("failed to write to file");
                println!("wrote dnskey tag: {} to: {}", key_tag, path.display());
            }
            _ => println!("unexpected response"),
        }
    }
}