akka/akka — pull request #16273 by viktorklang (2014-11-10 15:22:48+00:00)
Title: =str - Various Flow and FlowMaterializer improvements

THIS IS A WIP-BRANCH/PR for discussion and improvement, DO NOT MERGE YET

- Switches from using size-of-1/2 Vectors to using Lists
- Fixes an issue where processorForNode wouldn't use the dispatcher form the settings
- Adds a dedicated Collect fusion op
- Adds various simplifications to ActorBasedFlowMaterializer
- Adds FIXMEs where appropriate
- Switches `grouped` to use a VectorBuilder
- Adds support for `scan`