How is event time processing implemented in Apache Beam?

In Apache Beam, event time processing is achieved through Timestamps and Watermarks.

1. Timestamps are used to indicate the time when events occur. In a data stream, each element has a corresponding Timestamp that represents the time when the event of that element occurred. The TimestampAssigner can be used to assign a Timestamp to each element. In Apache Beam, WithTimestamps or WithTimestampsAndEventTime can be used to assign Timestamps to elements in a data stream.
2. Watermarks indicate the progress of event time by showing that all events before it have arrived and there won’t be any earlier events. They can trigger window operations like computations or closing windows. In Apache Beam, you can generate Watermarks using TimestampWatermark or AssignsWatermarks.

By using Timestamps and Watermarks, Apache Beam can handle event time processing, including windowing operations, latency considerations and more.