There's no nice way for the client to disconnect a PartitionConsumer stream

The [`stream` method in `PartitionConsumer` ](https://infinyon.github.io/fluvio-client-node/classes/_index_.partitionconsumer.html#stream) will never finish. This causes [the consume example](https://github.com/infinyon/fluvio-client-node/blob/e6085a6441931cd953c4b3704a0cc3769e363e40/examples/consume.ts#L66) to never finish.

One method for ending the stream on the client side is to wrap the [stream call in a promise like the integration tests do](https://github.com/infinyon/fluvio-client-node/blob/e6085a6441931cd953c4b3704a0cc3769e363e40/src/fluvio.spec.ts#L321-L342). This is a bit gross and should be abstracted.