jboner/akka — comment on commit 57de4c969c59f7b726e08fe260a0596385399cb5
File: akka-testkit/src/main/scala/akka/testkit/TestKitExtension.scala line 20
By patriknw:

I wonder if it isn't better if registerExtension looked like
def registerExtension[T <: AnyRef](key: ExtensionKey[T], ext: Extension[T])
and that init doesn't return Key, but Unit.
I think that makes it easier to make register and init atomic.