```rust
async fn main() { use std::collections::BTreeMap; use surfheader::Header; use surfheader::parsetosurfheader; let h = r##" GET / HTTP/1.1 Host: crates.io Upgrade-Insecure-Requests: 1 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/106.0.5249.119 Safari/537.36 Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9 Referer: https://crates.io/ Accept-Encoding: gzip, deflate Accept-Language: en-US,en;q=0.9 Connection: close "##; let info = parsetosurfheader(h).unwrap(); let mut req = surf::get(info.url).build(); req.headers(info.headers); let client = surf::Client::new(); let mut res = client.send(req).await.unwrap(); println!("{:?}",res.body_string().await.unwrap()); } ```