FlatMapFunction wrapper over Beam DoFn.SimpleDoFnRunner.Pipeline with Gearpump.PipelineRunner that executes the operations in the pipeline by first translating them
to Gearpump Stream DSL and then executing them on a Gearpump cluster.GearpumpPipelineOptions.GearpumpRunner.BoundedSourceWrapper and UnboundedSourceWrapper.GroupByKey is translated to Gearpump groupBy function.StepContext that basically does nothing.Read.Bounded is translated to Gearpump source function and BoundedSource is
wrapped into Gearpump DataSource.Read.Unbounded is translated to Gearpump source function and UnboundedSource is
wrapped into Gearpump DataSource.PipelineRunner for tests, which uses EmbeddedCluster.PTransform to Gearpump functions.TransformTranslators.Iterable.Window.Assign is translated to Gearpump flatMap function.