Ordered GroupBy Operator

[thomasnield]

Hey David, some time ago you created some helpful Transformers in this library that buffers sequential items while they are equal or a condition yields true.

How hard would it be to do the same thing with a GroupedObservable?
http://stackoverflow.com/questions/39354421/rxjava-creating-a-groupbyuntilchanged-operator

I imagine it would be helpful to break a large Observable source's emissions into finite GroupedObservables based on a condition or a distinct value.