What does putting "type intersection" in the parameter list for RequestListener mean?

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Putting "type intersection" in the parameter list for RequestListener means that the listener will receive notifications only for requests that match all of the specified types. For example, if the parameter list includes "GET" and "json" as types, the listener will be notified only of GET requests that have a JSON content type. This allows for more fine-grained control over which requests a listener should handle.