extract Raw Detail Bytes
Extract the raw inner bytes of the <detail> element, verbatim.
The escape hatch for callers that want to ship a <detail> block the structured parser doesn't model — the bytes go into TakPacketV2Data.Payload.RawDetail and are re-emitted unchanged by CotXmlBuilder, preserving attribute order and whitespace byte-for-byte. Pure regex (no XML reader), matching the inside of the first <detail …>…</detail>.
Return
the UTF-8 bytes between the <detail> tags, or an empty array if there is no <detail> element.
Parameters
cot Xml
a full CoT XML event string.