Scala Notes

1. A function calling async function should return a future too.

def foo (b: B) : Future[A] {
    val c = aync {
       ...
    }

2. access a future:

 for {
      s <- c
   } yield {
      ...
   }
}

3. change a list of future to future of list
Future.sequence(x)

4. wrap anything with Future:
sync(None)