code: public static <T, R extends Collection<T>> Transformer<T, R> collectWhile(
              final Func0<R> factory, final Action2<? super R, ? super T> collect) {
          return collectWhile(factory, collect, HolderEquals.<T> instance());
      }
docs: <p>
  Returns a {@link Transformer} that returns an {@link Observable} that is
  collected into {@code Collection} instances created by {@code factory}
  that are emitted when items are not equal or on completion.
  
  <p>
  <img src=
  "https://github.com/davidmoten/rxjava-extras/blob/master/src/docs/collectWhile.png?raw=true"
  alt="marble diagram">
  
  @param factory
  collection instance creator
  @param collect
  collection action
  @param <T>
  generic type of source observable
  @param <R>
  collection type emitted by transformed Observable
  @return transformer as above