Function read_http_response 

fn read_http_response<C: Read + Write>(
    connection: &mut C,
    local_port: u16,
    host: &str,
    path: &str,
    range_from: Option<usize>,
) -> Result<(Vec<u8>, bool), &'static str>

HTTP 要求を送り、応答全体を読む（TLS 1.3 / 1.2 共通）。