https://beam.apache.org/releases/javadoc/2.71.0/org/apache/beam/sdk/values/PCollectionViews.InMemoryMultimapViewFn.html
PCollectionViews.InMemoryMultimapViewFn (Apache Beam 2.71.0)
declaration: package: org.apache.beam.sdk.values, class: PCollectionViews, class: InMemoryMultimapViewFn
apache beam