The Publisher contract
Publisher only sends what Subscriber requested. Never more.
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The Publisher contract
Publisher only sends what Subscriber requested. Never more.
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request(N) propagates
Subscriber calls subscription.request(10). Publisher sends up to 10. Downstream signals when ready for more.
Operators + backpressure
Most operators pass demand through. Some (buffer, sample) transform demand semantics.
When it breaks
Non-honoring publisher (e.g., wrapping a raw callback) can flood. Use onBackpressureBuffer or onBackpressureDrop.
Reactive vs virtual threads
VTs make reactive less necessary for I/O. Reactive still wins for streaming transformations + explicit backpressure semantics.