question: private Observable < ? > handleObservableOnWorkerThread ( final Method invokedMethod , final Object [ ] args ) throws Throwable { Observable < ? > result = ( Observable < ? > ) invokedMethod . invoke ( userImpl , args ) ; if ( result != null ) { return result . subscribeOn ( AndroidSchedulers . handlerThread ( serviceThread . getHandler ( ) ) ) ; } else { return null ; } }
target:  Subscribe observable invocation to the worker thread queue.