import type { coresdk } from '@temporalio/proto';
/**
 * Collects the count, total size, participating drivers, and duration of external-storage
 * operations performed while processing one task, in one direction (all stores, or all retrieves).
 *
 * @internal
 * @experimental
 */
export declare class ExternalStorageMetricsAccumulator {
    private payloadCount;
    private totalSizeBytes;
    private readonly driverNames;
    private readonly intervals;
    /**
     * Record one completed driver operation: `payloadCount` payloads totalling `sizeBytes`, which
     * ran over the monotonic-clock span `[startMs, endMs]`.
     */
    record(driverName: string, payloadCount: number, sizeBytes: number, startMs: number, endMs: number): void;
    /**
     * The proto metrics, or `undefined` when no external storage occurred (so the completion field
     * is left unset).
     */
    toProto(): coresdk.common.IExternalStorageMetrics | undefined;
}