Requiring 'static for FilesystemMT seems too strict

[pedrocr]

I'm trying to keep a reference to part of my FilesystemMT implementation to be able to have concurrent threads managing state (e.g., sync to disk every X seconds). The signature of FuseMT::new() requires 'static which makes this harder to do. Would it make sense to use crossbeam::scope or something similar to allow having both the fuse_mt and implementation threads run properly scoped?

[pedrocr]

Here's the hack I had to implement to make it work right now:

https://github.com/pedrocr/syncer/blob/4afc7620ce66fbb57425819502570936d898e159/src/lib.rs

It seems to work fine and shouldn't actually be all that unsafe but it would be nice if there was some standard way of having helper threads controlled by the implementation to do housekeeping tasks in the background.