Hi all, I've been working on adding MultimapState support to the Dataflow Runner, and the state interface is currently missing from the Beam State API.
I have an one pager proposing its API interface in https://docs.google.com/document/d/1zm16QCxWEWNy4qW1KKoA3DmQBOLrTSPimXiqQkTxokc/edit#. Please share suggestions/comments! Thanks! Buqian Zheng
