Hello, We're implementing a streaming outer join operator based on a TwoInputStreamOperator with an internal buffer. In our use-case only the items whose timestamps are within a several-second interval of each other can join, so we need to synchronize the two input streams to ensure maximal yield. Our plan is to utilize the watermark mechanism to implement some sort of a "throttling" operator, which would take two streams and stop passing through one of them based on the watermarks in another. However, there doesn't seem to exist an operator of the shape (A,B)->(A,B) in Flink, where A and B can be received and emitted independently. What would be a resource-saving way to implement such (e.g., without spawning two more parallel TwoInputStreamOperators)?
Alex
