i think that it is feasible to do, but i think that the issue was that when i last looked, there wasn't an explicit way to mark something as potentially blocking

or, there was, but we'd need to instrument a lot of stuff that currently just runs directly on the iopool in a more finegrained manner...?

basically, iirc, tokio-fs internally used a "maybe blocking" block, but it wasn't 100% clear whether we could just wrap each of the `Fn`s that we currently submit to the io pool using the same mechanism, and have it work

i also think that i got sidetracked into attempting to make things more finegrained here: https://github.com/tokio-rs/tokio/issues/369

i expect that since then they have actually implemented a lot of those methods... but if you see my final comment there, it sortof feels like wrapping an entire sequence of IO operations in a blocking-block is better for some of our io-pooly usecases anyway

...yea, they're all implemented now. so all FS access could happen via tokio-fs, probably

the last thing(s) though would be lmdb and curl

commented on https://github.com/tokio-rs/tokio/issues/369 and closed it in favor of the linked tickets

https://github.com/tokio-rs/tokio/issues/726 in particular is troubling

although it's unclear whether it is a symptom of incorrect usage of those APIs

it's probably worth dumping this in a ticket, sorry.