Function validate_client_path_transport 

pub fn validate_client_path_transport(
    parameters: &[KeyValuePair],
    over_webtransport: bool,
) -> Result<(), SetupError>

Refuse a PATH parameter on a session that is not native QUIC.

The same sentence in Section 9.3.2.2 forbids PATH “when WebTransport is used” and closes the session with Invalid Path on one received there. Which transport carries the session is known to the connection and not to the endpoint, so this is a separate call rather than part of validate_client_setup.

Errors

SetupError::PathOverWebTransport if a PATH is offered over WebTransport.