Extend LeaseManager to support Leases as AutoCloseable resources

[keeferrourke]

Scratching an itch with the Lease interface.

Here's an implementation independent extension function to make leases auto-closeable.

Intention is to use it like:

@Inject lateinit val LeaseManager leaseManager

leaseManager.acquireOrNull("some-lease")?.use { lease ->
  /* Do critical stuff that needs the lease */
}

[keeferrourke]

Dunno if this is the right place for this test.

[aerb]

Like the direction! Just some thoughts on the API.

[aerb]

One potential downside of this is it's still possible to acquire and then forget to close a lease. I've seen the useX convention used in the kotlin stdlib that avoids this by just accepting a lambda directly. Example that jumps to mind is the useLines method.
Eg:

File("").useLines { lines -> println(lines) }

This may be a bit awkward her - I'm not sure what the behavior should be if you can't acquire ...

[keeferrourke]

You raise a good point, which is also still a problem with the prescribed usage without this extension.
Leases are held only for some time, so if a user forgets to close the lease, it will be let go eventually.

Something like leaseManager.useLease { lease -> ... } would be nicer from that perspective, however it would probably have to come with the stipulation that the lambda doesn't run if the lease can't be acquired. Unsure if that would be surprising. Perhaps leaseManager.maybeUseLease { lease -> ... }? Dunno! 🤷