/**
 * A native `Headers` that also answers to bracket access.
 *
 * `.get('etag')` is the shape a fetch `Response` produces; `['etag']` is the shape axios
 * produced and what consumers outside this repo were written against. Supporting both
 * keeps the axios removal invisible to them.
 */
export interface HttpHeaders extends Headers {
    [key: string]: any;
}
/**
 * Views a native `Headers` as {@link HttpHeaders}.
 *
 * Enumeration (`Object.keys`, spread, `JSON.stringify`) yields the lowercase header names,
 * matching what axios put on its response headers object. Bracket access is
 * case-insensitive, which axios's was not, and resolves to `undefined` rather than `null`
 * for an absent header — again what a plain object did.
 */
export declare const httpHeaders: (headers: Headers) => HttpHeaders;