/**
 * Token bucket rate limiter.
 *
 * Standalone utility — does not import from any other local module.
 */
/**
 * Token bucket rate limiter using a continuous-refill token bucket.
 *
 * Tokens accumulate at `tokensPerSecond` up to a maximum of `maxBurst`.
 * `consume()` blocks until the requested number of tokens are available,
 * servicing concurrent callers in FIFO order.
 */
export declare class TokenBucket {
    private readonly tokensPerSecond;
    private readonly maxBurst;
    /** Current number of available tokens (fractional allowed). */
    private available;
    /** Timestamp (ms) of the last refill computation. */
    private lastRefillTime;
    /** FIFO queue of consumers waiting for tokens. */
    private readonly queue;
    /** Handle to the refill interval, or `null` when disposed. */
    private intervalId;
    /**
     * @param tokensPerSecond - Rate of token refill (default: 5).
     * @param maxBurst - Maximum accumulated tokens (default: 10).
     */
    constructor(tokensPerSecond?: number, maxBurst?: number);
    /**
     * Refill tokens based on elapsed wall-clock time since the last refill,
     * then service as many queued consumers as possible in FIFO order.
     */
    private refill;
    /**
     * Fulfill queued consumers in FIFO order while tokens are sufficient.
     * A consumer whose requested `count` exceeds `maxBurst` is auto-allowed
     * (it would otherwise deadlock forever) and drains the bucket to zero.
     */
    private drainQueue;
    /**
     * Wait until `count` tokens are available, then consume them.
     *
     * Resolves immediately if enough tokens are available, otherwise waits
     * for refill. Concurrent callers are serviced in FIFO order.
     *
     * @param count - Number of tokens to consume (default: 1).
     */
    consume(count?: number): Promise<void>;
    /**
     * Try to consume tokens without waiting. Returns `true` if successful,
     * `false` if insufficient tokens are currently available.
     *
     * @param count - Number of tokens to consume (default: 1).
     */
    tryConsume(count?: number): boolean;
    /**
     * Get current bucket state.
     *
     * @returns An object with the current available tokens, the max burst
     * capacity, and the refill rate (tokens per second).
     */
    getStats(): {
        available: number;
        maxBurst: number;
        rate: number;
    };
    /**
     * Stop the refill timer and clean up. Any pending consumers are rejected
     * with an Error. Subsequent calls to `consume()` will reject and
     * `tryConsume()` will return `false`.
     */
    dispose(): void;
}
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