/**
 * Conditional GETs via ETags. Opt a route in with `meta: { etag: true }`: the
 * pipeline hashes the response body into a strong `ETag`, and when the client's
 * `If-None-Match` matches it replies `304 Not Modified` with no body — saving
 * bandwidth without the handler doing anything. Adapter-agnostic (it runs in the
 * shared `runRoute` pipeline).
 */
/** A strong ETag for a serialized body: quoted sha1 (base64url). */
export declare function computeEtag(body: string): string;
/** Whether an `If-None-Match` header (`*`, or a comma-separated list) matches `etag`. */
export declare function ifNoneMatchSatisfied(header: string | undefined, etag: string): boolean;