Function dial_quic_to 

pub async fn dial_quic_to(
    target: &QuicTarget,
    options: &QuicDialOptions,
) -> Result<(Transport, Option<Vec<u8>>), DialError>

Dial one already-resolved address, and report which ALPN the server chose.

This is the whole dial with nothing decided for the caller: one address, one server name, one ALPN offer, one answer. dial_quic is the convenience wrapper that resolves a host:port and picks an address; a caller measuring which address or which name a relay answers on wants this one, so that each attempt fails on its own and is recorded on its own.

The second return value is the protocol the server chose from options.alpn, None if it selected none. DraftVersion::from_alpn names a draft for five of the six; drafts 07-14 share moq-00 and settle their version in CLIENT_SETUP.

The endpoint is dropped when the dial returns — quinn keeps the connection’s driver alive independently.