rxgroups/src/main/java/com/airbnb/rxgroups/ObservableGroup.java
public void unlock() {
    locked = false;
    forAllObservables(new Consumer<ManagedObservable<?>>() {
      @Override
      public void accept(ManagedObservable<?> managedObservable) {
        managedObservable.unlock();
      }
    });
  }
public void unlock() {
    locked = false;
    forAllObservables(new Consumer<ManagedObservable<?>>() {
      @Override
      public void accept(ManagedObservable<?> managedObservable) {
        managedObservable.unlock();
      }
    });
  }
Unlocks (releases) Observables added to this group to emit new events until they are locked,
unsubscribed or cancelled.