A simple utility class for interop between RxJava and Guava's ListenableFuture. It also features a static factory GuavaTranformers class which transforms an Observable<T> into the following Guava collections.
Observable<ImmutableList<T>>
Observable<ImmutableSet<T>>
Observable<ImmutableMap<K,T>>
Observable<ImmutableListMultimap<K,V>>