rust async read tcp stream as header to string

header_reader.rs

pub async fn read_headers<R>(reader: R) -> Result<String>
where
    R: AsyncRead + std::marker::Unpin,
{
    let mut request_string = String::new();
    let mut reader = BufReader::new(reader);
    loop {
        let byte = reader.read_line(&mut request_string).await?;
        if byte < 3 {
            break;
        }
    }
    Ok(request_string)
}