Add predefined Aggregations for ChangeStreams [DATAMONGO-2088]

[spring-projects-issues]

Christoph Strobl opened DATAMONGO-2088 and commented

It would be a nice addition to ChangeStreams if we'd have predefined Aggregations for eg. insert operations.

Flux changeStream = reactiveTemplate
	.changeStream(newAggregation(match(where("operationType").is("insert"))),
				Person.class, ChangeStreamOptions.empty(), "person");

So that one is able to write

Flux changeStream = reactiveTemplate
	.changeStream(INSERTS, Person.class, ChangeStreamOptions.empty(), "person");

---

No further details from DATAMONGO-2088