- With probing the packet rate can get high suddenly and remote may not
have sent receiver report as it might be sending for the non-spikey
rate. That causes metadata cache overflows. So, give RTX more cahe.
- Don't need a large cache for primary as either reports come in
regularly (or they are missing for a long time and having a biger
cache is not the solution for that, so reduce primary cache size)
- Check for receiver report falling exactly back by (1 << 16). Had done
that change in the inside for loop, but missed the top level check :-(
