// Returns false for invalid header name. public static bool TryGet(ReadOnlySpan <byte> headerName, out HeaderDescriptor descriptor) { Debug.Assert(headerName.Length > 0); KnownHeader?knownHeader = KnownHeaders.TryGetKnownHeader(headerName); if (knownHeader != null) { descriptor = new HeaderDescriptor(knownHeader); return(true); } if (!HttpRuleParser.IsToken(headerName)) { descriptor = default(HeaderDescriptor); return(false); } descriptor = new HeaderDescriptor(HttpRuleParser.GetTokenString(headerName)); return(true); }