[Bug]: Triggers with session window not working

[boolangery]

What happened?

Unable to trigger early firings with a session window.

Tried triggers:

windowedUpdates := beam.WindowInto(s,
	window.NewSessions(30*time.Second), propUpdates,
	beam.Trigger(trigger.Repeat(trigger.AfterCount(500))),
	beam.Trigger(trigger.Repeat(trigger.AfterProcessingTime().PlusDelay(60*time.Second))),
	beam.PanesDiscard(),
)

windowedUpdates := beam.WindowInto(s,
	window.NewSessions(30*time.Second), propUpdates,
	beam.Trigger(trigger.AfterEndOfWindow().EarlyFiring(trigger.AfterProcessingTime().PlusDelay(60*time.Second))),
	beam.PanesDiscard(),
)

Context:

• Streaming pipeline
• PubSub input
• Printing output after a groupBy
• Sending one message every second

Result: The window extend indefinitely and no panes are fired

Issue Priority

Priority: 3 (minor)

Issue Components

• [ ] Component: Python SDK
• [ ] Component: Java SDK
• [X] Component: Go SDK
• [ ] Component: Typescript SDK
• [ ] Component: IO connector
• [ ] Component: Beam YAML
• [ ] Component: Beam examples
• [ ] Component: Beam playground
• [ ] Component: Beam katas
• [ ] Component: Website
• [ ] Component: Spark Runner
• [ ] Component: Flink Runner
• [ ] Component: Samza Runner
• [ ] Component: Twister2 Runner
• [ ] Component: Hazelcast Jet Runner
• [X] Component: Google Cloud Dataflow Runner