Summary:
This adds an optional exit strategy that reacts to the client disconnecting rather than a `SIGINT` which can be used for integration tests.
`MiddlewareAPI` is a subset of `Store` and required to work here.
Annoyingly, it's not quite clear to me why this does not work as part of an event loop cycle and requires a `setTimeout`. This doesn't have any negative effects and works in the same way that the SIGINT interruption works, but it's a bit of an eyesore.
Reviewed By: danielbuechele
Differential Revision: D14622111
fbshipit-source-id: e2caca056e478428d977565dc9bc09eefca4230c
b20d0a4c8b