/**
 * Split a Unix epoch interval into sub-intervals of `amount × unit`.
 *
 * - Returns an array of `{ start, end }` records that tile the interval.
 * - The final sub-interval is trimmed so its `end` never exceeds the original `end`.
 * - Returns `[{ start, end }]` when `start === end` (zero-length interval).
 * - Returns `[]` on invalid input (non-finite/non-integer start/end, unsupported unit,
 *   non-positive amount, or invalid timeZone).
 *
 * Uses the system timeZone for calendar-unit arithmetic (consistent with `addUnix`).
 *
 * @param start Unix epoch value (seconds or milliseconds) — interval start
 * @param end Unix epoch value (seconds or milliseconds) — interval end
 * @param unit duration unit string — any `DateTimeDurationUnit`
 * @param amount positive number of units per step
 * @returns array of `{ start, end }` records, or [] on invalid input
 *
 * @example splitIntervalByUnitUnix(0, 86400000, "hour", 6) // [{ start: 0, end: 21600000 }, { start: 21600000, end: 43200000 }, { start: 43200000, end: 64800000 }, { start: 64800000, end: 86400000 }]
 * @example splitIntervalByUnitUnix(0, 3600000, "hour", 1) // [{ start: 0, end: 3600000 }]
 * @example splitIntervalByUnitUnix(0, 0, "hour", 1) // [{ start: 0, end: 0 }]
 * @example splitIntervalByUnitUnix(0, 86400000, "hour", 0) // []
 * @example splitIntervalByUnitUnix("invalid", 86400000, "hour", 1) // []
 */
export declare function splitIntervalByUnitUnix(start: number | string, end: number | string, unit: string, amount: number): Array<{
    start: number;
    end: number;
}>;