Function hop_by_hop_header_names 

pub fn hop_by_hop_header_names(
    headers: &HeaderMap,
) -> impl Iterator<Item = HeaderName> + use<>

Available on crate features http and std only.

Return known hop-by-hop field names and removable Connection nominations.

Early-Data is preserved even when nominated, as RFC 8470 section 5.1 requires for requests. Use connection_header_names for raw nominations, or remove_hop_by_hop_response_headers to sanitize a response.

Known names are included even when absent from the map. The iterator owns its nominations so callers may mutate the map while consuming it.