Exception safety guarantees

[hu55a1n1]

basecoin-rs doesn't provide any exception safety guarantees as of now. The reason for this is that we only provide a volatile in-memory data store currently. But this is definitely something we should address.

Proposal

One way to provide strong guarantees and the ability to recover from crash failures would be to record pending data-store changes on failure. This can be done in a couple of ways ->

• std::panic::set_hook() and panic_any!() to pass the app state to the panic handler and printing pending writes from the RevertibleStore.
• Using RevertibleStore's Drop to write the pending writes to stderr.