{
  "id": "06-eventstream",
  "title": "EventStream",
  "problem": "Existing event-streaming systems (Kafka, Pulsar, Redpanda) treat backpressure as an afterthought — slow consumers either drop messages, lag indefinitely, or trigger broker-level fan-out failures. Modern application workloads (especially LLM-pipelined ones) need first-class backpressure semantics that the producer can observe in-band.",
  "targetUser": "Platform engineers at companies running event-driven infrastructure at moderate scale (100k–10M events/day) where consumer lag matters and Kafka's operational complexity is unwelcome.",
  "desiredOutcome": "A Go-native streaming system where producers receive backpressure signals as a first-class part of the protocol, and consumer-driven flow control is the default.",
  "initialHypothesis": "Teams will adopt a Kafka alternative if (a) operations are 10× simpler — single binary, no ZooKeeper, no Schema Registry — and (b) backpressure is a first-class protocol feature, not a config flag.",
  "constraints": [
    "Wire-compatible with Kafka producer protocol for migration safety",
    "Single binary, single config file, runs on a single node up to 100k events/sec",
    "Apache 2.0 license"
  ],
  "meta": {
    "isHoldout": false,
    "expectedDifficulty": "hard",
    "testsFor": ["technical", "infra", "metamodel-strain"]
  }
}