pub async fn probe(
client: &Client,
url: &Url,
) -> Result<RemoteInfo, TransferError>Expand description
Ask the server what it has, without downloading it.
A one-byte ranged GET rather than HEAD: plenty of servers and CDNs
answer HEAD with different (or absent) headers than they answer GET,
and a ranged GET tells us in one round trip whether ranges actually work
— as opposed to whether the server merely claims they do.
Prefer probe_priming for the primary URL; this remains the right call for
mirrors, where we want the metadata and emphatically not the body.