Currently our documentation states that change streams are not usable in JRuby. As far as I can tell this is because the Enumerable interface, which is what #to_enum produces, in JRuby performs background buffering which ends up reading data ahead of when the application requests it, resulting in unexpected behavior.

However with try_next it is possible to use change streams in JRuby because this avoids Enumerable entirely.

In scope for this ticket:

1. Add documentation to tutorial stating that for JRuby the supported way to use change streams is via ChangeStream#try_next.
2. Go through change stream tests and add variations of them using try_next as documented.
3. Mark all change stream tests not using try_next with only_mri.