The library they referenced (Finagle) does pretty much just that. A few things that leapt out at me: - It's hard to figure out what the dependency graph looks

The library they referenced (Finagle) does pretty much just that. A few things that leapt out at me: - It's hard to figure out what the dependency graph looks like just from promises - That pattern is verbose and results in gross types when you do it in Java - With this library, you can easily profile parts of the algorithm to see what's going slow, what's taking a bunch of memory, etc.