Where

Keeps the events whose payload satisfies a predicate.

Lifetimes pass through unchanged: an event either appears in the output with its own lifetime, or not at all.

In the diagram, a:1 fails Value > 1 and is dropped; b:2 and a:3 keep their lifetimes [3,9) and [6,8).

See also: Select, Distinct, SelectMany, WhereNotExists