It's nice to have this platform available though.
I played with IronWorkers a lot and even built some tooling around spinning up a worker and long polling an IronCache waiting for output (yes, it was a little gnarly). I'm really excited to play with this.
And for the those cases, where it is a big deal, the next two major milestones on the roadmap aim to work around that issue, namely hot containers and streaming input. https://github.com/iron-io/functions#roadmap . Once that's in place, it should perform similar to any API.
It does work also with Java lambda apps, you can import them straight from AWS Lambda API using the CLI app.