/**
 * Main-thread side of the Whistle engine: one warm `worker_threads` Worker
 * that holds the WASM engine and the model, requests answered in order, and a
 * fresh worker after a crash.
 *
 * The worker is unreferenced while idle, so a warm engine never keeps the
 * process alive on its own; it is referenced again while a request is open.
 *
 * @module voice/whistle/engine
 */
import type { WhistleAssetPaths, WhistleEngineOutput, WhistleStreamStep } from "../../types/index.js";
export declare class WhistleEngine {
    private readonly paths;
    private worker;
    private ready;
    private nextId;
    private readonly pending;
    constructor(paths: WhistleAssetPaths);
    /** Batch transcription of 16 kHz mono samples; long audio is chunked in the worker. */
    transcribe(pcm: Float32Array, language: string | null, keywords: string | null, timestamps: boolean): Promise<WhistleEngineOutput>;
    /** Feed about a second of samples to the engine's native stream. */
    streamProcess(pcm: Float32Array, language: string | null, keywords: string | null): Promise<WhistleStreamStep>;
    /** Flush the stream's tail and reset its state. */
    streamStop(): Promise<WhistleStreamStep>;
    /** Terminate the worker; the next call starts a new one. */
    dispose(): Promise<void>;
    private request;
    private start;
    /** Drop a dead worker: reject what it held, and let the next call start a new one. */
    private crash;
    private failAll;
}