Help with getting ICMPv6 payload in Lua detection from icmpv6.hdr and needs["buffer"] = tostring(true)?

I’m just trying to reliably get the ICMPv6 payload contents in Lua detection script, for a project.
I would like to know if the “needs[“buffer”] = tostring(true)” can supply the sticky buffer from the icmpv6.hdr to Lua detection, when icmpv6.hdr and content: is used in a rule? When I try a simple Lua script with the needs statement, buffer is always nil.
I noticed this link Feature #2937: sticky buffer access from lua script - Suricata - Open Information Security Foundation but wasn’t clear if it is working.
Or, is there a reliable way to get the ICMPv6 payload in Lua detection, since SCPacketPayload, or the “needs[“payload”] = tostring(true)” isn’t necessarily giving the ICMPv6 payload.

Thank you