Routine ships with a default adapter for router. This child module contained herein is additional adapter for RxJava2.
Supply an instance of rxjava2 adapter when building your Routine instance:
Routine routine = new Routine.Builder()
.addAdapter(RxJava2AdapterFactory.create())
.build();compile 'com.anbillon.routine:adapter-rxjava2:1.1.1'