/** Per-sender rate limiter for incoming XMTP messages.
 *
 *  Tracks timestamps of recent messages per sender and rejects messages
 *  that exceed the configured rate. Stale entries are cleaned up on a
 *  configurable interval.
 */
export declare class RateLimiter {
    private readonly _limits;
    private readonly _maxPerMinute;
    /** M-6: Maximum number of tracked senders to prevent unbounded memory growth */
    private readonly _maxSenders;
    private _cleanupInterval;
    /** @param maxPerMinute Maximum messages per sender per minute (default 10)
     *  @param maxSenders Maximum tracked sender entries before eviction (default 10_000) */
    constructor(maxPerMinute?: number, maxSenders?: number);
    /** Check whether a sender is within their rate limit.
     *
     *  Records the current timestamp if allowed.
     *
     *  @param sender - Sender identifier (typically an address)
     *  @returns `true` if the message is within the limit, `false` if rate-limited
     */
    checkLimit(sender: string): boolean;
    /** Get remaining message quota for a sender within the current minute window */
    getRemainingQuota(sender: string): number;
    /** Purge expired entries from all senders */
    private _cleanup;
    /** Stop the cleanup timer and clear all state */
    destroy(): void;
}
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