import { AsyncLocalStorage } from 'node:async_hooks';
/** A stream of transcription events to surface from {@link runStt}, or `null` when none is bound. */
export type ObservationQueue = AsyncIterable<unknown> | null;
/** Active {@link ObservationQueue} for the current async context, set by the surrounding session. @internal */
export declare const sttObservationStore: AsyncLocalStorage<ObservationQueue>;
/** Drain `audioStream` and yield transcription events from the bound {@link ObservationQueue} (yields nothing if none is bound). */
export declare function runStt(audioStream: AsyncIterable<unknown>): AsyncGenerator<unknown>;
/** A list collecting the text chunks forwarded by {@link runTts}, or `null` when none is bound. */
export type TtsHookSink = Array<unknown> | null;
/** Active {@link TtsHookSink} for the current async context, set by the surrounding session. @internal */
export declare const ttsHookSinkStore: AsyncLocalStorage<TtsHookSink>;
/**
 * Drain `textStream`, forwarding each non-null chunk to the bound {@link TtsHookSink}
 * (the stream is consumed without forwarding when none is bound). Yields nothing;
 * the forwarded text is spoken by the pipeline's synthesis.
 */
export declare function runTts(textStream: AsyncIterable<unknown>): AsyncGenerator<unknown>;