How does stateless HTTP mode solve the horizontal scaling problem?

Setting stateless_http to true eliminates the coordination problem by removing all state. Clients do not receive session IDs, so the server cannot track them. The GET SSE pathway becomes unavailable, meaning no server-to-client requests, no sampling, no progress reports, and no subscriptions. However, any instance can handle any request because there is no state to synchronize. Client initialization is no longer required, so clients make requests directly without the handshake, trading reduced functionality for easy scaling.