How does Apache Beam handle delayed data processing?

In Apache Beam, delayed data processing is handled using windows and triggers. Windows define the time range of the data stream, while triggers define when the computations within the window should be triggered.

The main steps for delaying data processing are as follows:

1. Window definition: Define windows based on data timestamps and window size, which can be either fixed-size time windows or session windows based on event time.
2. Trigger settings: Specify when to trigger computations in the window based on conditions such as water levels, element quantity, or processing time.
3. Perform calculations: Trigger calculations in the window based on the conditions of the trigger and process delayed data.

Apache Beam provides a rich API for windows and triggers when dealing with delayed data, allowing users to flexibly define windows and triggers for efficient delayed data processing. Additionally, Apache Beam also offers a variety of window functions and trigger functions, making it easy for users to customize window and trigger logic based on their specific needs.