import type { TokenUsage } from '../types.js';
declare const STREAM_USAGE: unique symbol;
export type UsageTrackedStream = ReadableStream<string> & {
    [STREAM_USAGE]?: Promise<TokenUsage | undefined>;
};
export declare function createStreamUsageTracker(): {
    promise: Promise<TokenUsage | undefined>;
    resolve: (usage: TokenUsage | undefined) => void;
};
export declare function attachStreamUsage(stream: ReadableStream<string>, usage: Promise<TokenUsage | undefined>): UsageTrackedStream;
export declare function getStreamUsage(stream: ReadableStream<string>): Promise<TokenUsage | undefined> | undefined;
export {};
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