system.reactive Getting started with system.reactive Ignoring repeated values

Example

There are two operators for filtering duplicates:

emails.Distinct(); // Never see the same value twice
emails.DistinctUntilChanged(); // Never see the same value twice in a row

You can also pass in a predicate:

emails.DistinctUntilChanged(x => x.Length); // Never see the same length email twice in a row