mongodb/mongo-java-driver — pull request #207 by rozza (2014-06-12 11:47:47+00:00)
Title: Ensure Async cursors can be cancelled

Refs: https://jira.mongodb.org/browse/JAVA-1259

Also added a `CancellableBlock` allows us to cancel getMores in rxJava and allows users more control.

Due to the way we wrap the async driver I had to manually test that unsubscribing works with observables. But we confirm it works with the async wrapper and rxJava confirms observable subscriptions work. So we follow the guidelines here: https://github.com/Netflix/RxJava/wiki/Implementing-Your-Own-Operators#other-considerations