Flux.create is another mechanism for generating events programmatically. It takes a FluxSink, which is capable of generating any number of events. The API is more generic than the Generate methods discussed in the previous section. The FluxSink is capable of generating events asynchronously. Moreover, it does not take subscription cancellation or backpressure into account. This means that even if the subscriber has cancelled its subscription, the create API will continue to generate events. All implementations must listen for the cancel event and explicitly initiate stream closure.
As for backpressure, the producer keeps generating the events without looking into any demand from the subscriber. These events are buffered and dropped ...