Coursera Principles of Reactive Programming course promotes RxScala.
RxScala brings Reactive Extensions to Scala. Rx was first implemented
for .NET, and is now being implemented in Java. The RxScala project is
an adaptor for RxJava. Its code is in a subdirectory the RxJava
repository.
This library is not yet finished. You have to expect breaking changes
in future versions.