That's not a marketing talk but an important technical term instead. See this for a quick reference: https://github.com/ReactiveX/RxJava/wiki/Backpressure .
It is important to understand before even thinking about using reactive streams in production.
It is absolutely marketing talk, there's other established terms for what that means but they elected to make up other terms. Perhaps they should take the lesson from this talk where they explicitly break down this exact term and explain what they REALLY mean in common terms.
https://www.youtube.com/watch?v=pOl4E8x3fmw