Sorry, forgot to mention - if we want to explore combining the buffer
address and truesize into a single void *, we could also exploit the
fact that our size ranges from aligned GOOD_PACKET_LEN to PAGE_SIZE, and
potentially encode fewer values for truesize (and require a smaller
alignment than 256). The prior e-mails discussion of 256 byte alignment
with 256 values is just one potential design point.

Best,

Mike