Allocator: consider allocation _rate_ quotas as well #660
Description
Skimming https://dl.acm.org/doi/pdf/10.1145/3658644.3690246 got me thinking that we might want to be able to use quotas to rate-limit allocations. I'm not sure what policies would look like, and how we might concisely express them in a few bits of quota state, but it could be a fun thing to think about.