Function is_removable_connection_header 

pub fn is_removable_connection_header(name: &HeaderName) -> bool

Available on crate features http and std only.

Whether a Connection nomination may remove this field from a request head.

RFC 8470 section 5.1 forbids intermediaries from removing Early-Data, even when a peer incorrectly nominates it. Parsing nominations and validating trailers must still see the original name; apply this exception only when sanitizing request heads (or a head whose direction is not yet known).