import type { NumberOfSeconds, PositiveInteger } from '@naturalcycles/js-lib/types';
import type { TransformOptions, TransformTyped } from '../stream.model.js';
export interface TransformWarmupOptions extends TransformOptions {
    /**
     * Target concurrency after warmup completes.
     */
    concurrency: PositiveInteger;
    /**
     * Time in seconds to gradually increase concurrency from 1 to `concurrency`.
     * Set to 0 to disable warmup (pass-through mode from the start).
     */
    warmupSeconds: NumberOfSeconds;
}
/**
 * Transform that gradually increases concurrency from 1 to the configured maximum
 * over a warmup period. Useful for scenarios where you want to avoid overwhelming
 * a system at startup (e.g., database connections, API rate limits).
 *
 * During warmup: limits concurrent items based on elapsed time.
 * After warmup: passes items through immediately with zero overhead.
 *
 * @experimental
 */
export declare function transformWarmup<T>(opt: TransformWarmupOptions): TransformTyped<T, T>;