`cargo bench` sets `cfg(test)`, causing us to hit some test-only
code in the router when benchmarking, throwing off our benchmarks
substantially. Here we swap from the `unstable` feature to a more
clearly internal feature (`_bench_unstable`) and also checking for
it when enabling test-only code.
Intended to be a cross-platform implementation of the
channelmonitor::Persist trait.
This adds a new lightning-persister crate, that uses the
newly exposed lightning crate's test utilities.
Notably, this crate is pretty small right now. However, due to
future plans to add more data persistence (e.g. persisting the
ChannelManager, etc) and a desire to avoid pulling in filesystem
usage into the core lightning package, it is best for it to be
separated out.
Note: Windows necessitates the use of OpenOptions with the `write`
permission enabled to `sync_all` on a newly opened channel's
data file.
