Data exchange between tasks (operators/sources) at streaming api runtime

[Ishwara Varnasi]

Hello,
I have a scenario where I've two sources, one of them is source of fixed
list of ids for preloading (caching certain info which is slow) and second
one is the kafka consumer. I need to run Kafka after first one completes. I
need a mechanism to let the Kafka consumer know that it can start consuming
messages. How can I achieve this?
thanks
Ishwara Varnasi