public static DnsMessage ParseMessage(ReadOnlySpan <byte> span, out int bytesConsumed)
{
var context = new DnsParseContext(span);
var message = new DnsMessage
{
QueryId = context.ReadUInt16(),
};
ushort flags = context.ReadUInt16();
int queryCount = context.ReadUInt16();
int answerCount = context.ReadUInt16();
int serverCount = context.ReadUInt16();
int additionalCount = context.ReadUInt16();
message.IsResponse = (flags & ResponseFlag) != 0;
message.Operation = (DnsOperation)((flags & OpCodeMask) >> OpCodeShift);
message.IsAuthoritativeAnswer = (flags & AuthoritativeMask) != 0;
message.IsTruncated = (flags & TruncationMask) != 0;
message.IsRecursionDesired = (flags & RecursionDesiredMask) != 0;
message.IsRecursionAvailable = (flags & RecursionAvailableMask) != 0;
message.ResponseCode = (DnsResponseCode)(flags & ResponseCodeMask);
