The `PollableChannelPublisherAdapter` is based on the poll model of the
`FluxSink` and iterate and poll downstream `PollableChannel` until
there is an item or `n > 0`.
Having `take(6)` we end up with the cancel from the downstream
`Subscriber` after the batch is filled, but at the same time we continue
to poll the upstream source because `n` is like `Long.MAX_VALUE`.
* The proper way to interact is check for the `!sink.isCancelled()`
as well.
This way cancelled `sink` won't "steal" data from other subscribers
Fix compatibility with the latest dependencies
* Upgrade to Gradle 4.1
* Upgrade as much dependencies as possible
* Fix MongoDB module to resolve deprecation in the latest driver
* Increase receive timeout in the `ResequencerTests`
* Restore generic argument for the method reference in the `ReactiveStreamsTests`
* Fix `WebFluxInboundEndpoint` for the compatibility with the latest Reactor API
46de69dbf2