/**
 * Tracks the usage of tokens.
 */
export declare class TokenMeter {
    private _inputTokens;
    private _outputTokens;
    /**
     * The number of input tokens used
     */
    get usedInputTokens(): number;
    /**
     * The number of tokens generated by a model
     */
    get usedOutputTokens(): number;
    /**
     * Get the current state of the token meter
     */
    getState(): TokenMeterState;
    /**
     * Log the usage of tokens
     */
    useTokens(tokens: number, type: "input" | "output"): void;
    /**
     * Get the difference between the current meter and another meter
     */
    diff(meter: TokenMeter | TokenMeterState): {
        usedInputTokens: number;
        usedOutputTokens: number;
    };
    /**
     * Log the usage of tokens on multiple meters
     */
    static useTokens(meters: null | undefined | TokenMeter | readonly TokenMeter[] | ReadonlySet<TokenMeter>, tokens: number, type: "input" | "output"): void;
    /**
     * Get the difference between two meters
     */
    static diff(meter1: TokenMeter | TokenMeterState, meter2: TokenMeter | TokenMeterState): {
        usedInputTokens: number;
        usedOutputTokens: number;
    };
}
export type TokenMeterState = {
    usedInputTokens: number;
    usedOutputTokens: number;
};