Prevent expired keys from needing to be written to disk (TTL support)

[shikhar]

With foyer's HybridCachePolicy::WriteOnEviction data whose TTL has expired need not be written to disk when being evicted from memory cache.

Depends on foyer-rs/foyer#983 as the currently-available filtering mechanism is based around entry size and current IO stats https://docs.rs/foyer/latest/foyer/struct.StorageFilter.html#method.filter

[ujjwalkirti]

Hey @shikhar , I was going through the repo and found this issue. I know you commented that this issue is dependent on some other issue, is there another workaround at all? I am learning rust and was wondering if I can help with this issue

[shikhar]

@ujjwalkirti no, this makes the most sense to unblock from foyer, it's not so bad that we'd want to hack around