These are chat archives for ReactiveX/RxJava
RxJava – Reactive Extensions for the JVM – a library for composing asynchronous and event-based programs using observable sequences for the Java VM.
window()expect boundaries to be driven by external events (external meaning not related to the "windowed" stream)
groupBy's groups must be consumed or else the sequence stalls for every group. Consequently, It won't cache all items indefinitely but it will cache group keys until the group is cancelled or the source ends.