/**
 * CityHash128 implementation for ClickHouse checksums.
 * Based on Google's CityHash and adapted for ClickHouse's specific usage.
 *
 * ClickHouse uses CityHash128 to checksum compressed blocks.
 */
/**
 * Compute CityHash128 of the given buffer (or sub-range).
 * Returns [lo, hi] as two bigints (UInt64 each).
 */
export declare function cityHash128(buf: Buffer, offset?: number, length?: number): [bigint, bigint];