'//' path produces async-h1 error, probably from being treated as a protocol-relative URL

[etherealvisage]

Consider the following minimal tide server:

#[async_std::main]
async fn main() -> Result<(), std::io::Error> {
    tide::log::start();
    tide::new().listen("127.0.0.1:2000").await?;
    Ok(())
}

If we then run curl against it:

~$ curl localhost:2000// 
curl: (52) Empty reply from server

The logging output contains:

tide::listener::tcp_listener async-h1 error
    error empty host

After guessing from the empty host bit that it's treating "//" as a protocol-relative URL; and we can confirm this by curling localhost:2000//test/a/b/c: the logging output says:

tide::log::middleware <-- Request received
    method GET
    path /a/b/c

I haven't gone digging for where this might be happening, but thought I'd open this issue in case it's a quick fix for someone else :-)

[Fishrock123]

Should be fixed in the next `async-h1 release