It would be helpful if this thorough of an example could live on the apache beam website, I think it would avoid a lot of confusion. I certainly found the way it handles windowing with triggers to be quite diffrent than say, Spark.
The link for the Apache Beam project has the hostname and domain transposed. The correct URL is: <a href="https://beam.apache.org/" rel="nofollow">https://beam.apache.org/</a>