decodeHeaders4
fun <H1 : Any, H2 : Any, H3 : Any, H4 : Any> decodeHeaders4(headers: Map<String, List<String>>, header1: Header<H1>, header2: Header<H2>, header3: Header<H3>, header4: Header<H4>): EitherNel<String, HeaderValues4<H1, H2, H3, H4>>(source)
Decodes four declared headers and accumulates validation errors across all four definitions.