/**
 * The Worker→Router event emitter (fd 3). Serializes each {@link WorkerEvent} as
 * one NDJSON line to an injected Writable. The default `serve()` (T4) passes the
 * fd-3 stream; tests pass an in-memory stream. Each event is written immediately
 * (one `write` per line) so streaming never stalls behind a buffer.
 */
import type { JsonValue, StopReason } from "./protocol.js";
/** Minimal write interface accepted by {@link createEmitter}. `NodeJS.WritableStream` satisfies this. */
export interface WriteSink {
    write(s: string): void;
}
export interface Emitter {
    text(text: string): void;
    done(result: string, stopReason?: StopReason): void;
    error(message: string): void;
    native(framework: string, event: JsonValue): void;
    /** The SDK-version handshake (additive-optional, §8 item B). Emit at most
     *  once, before any native/turn event. */
    hello(framework: string, sdkName: string | null, sdkVersion: string | null): void;
}
export declare function createEmitter(out: WriteSink): Emitter;
//# sourceMappingURL=emit.d.ts.map