Factory methods for Observer.
Factory methods for Observer.

samuelgruetter/RxScala,zhongdj/RxScala,ReactiveX/RxScala,hermanbanken/RxScala,jbripley/RxScala,samuelgruetter/RxScala,joohnnie/RxScala,zjrstar/RxScala,jbripley/RxScala,hermanbanken/RxScala,TracyLu/RxScala