/**
 * class for storing headers parse from MHTML
 *
 * Tries to somewhat mimic the behavior of the fetch-api Headers object, with
 * some differences, notably that it does no validation.
 */
export interface MhtmlHeaders extends Iterable<[string, string]> {
    /**
     * add a key-value pair
     *
     * If key is already present it will be appended.
     */
    append(key: string, value: string): void;
    /**
     * iterate over all key-value pairs
     *
     * Multiple values for the same key will be joined in the order they were
     * added by `delimiter`.
     */
    entries(delimiter?: string): IterableIterator<[string, string]>;
    /**
     * iterate over all key-value pairs
     *
     * Multiple values for the same key will get iterated in the order they were
     * added.
     */
    entriesAll(): IterableIterator<[string, string]>;
    /**
     * get the value for a key
     *
     * If the key is missing, null will be returned, if multiple values for the
     * key are present, they will be joined be `delimiter`.
     */
    get(key: string, delimiter?: string): string | null;
    /** get all values for a key */
    getAll(key: string): string[];
    /** whether key has any values associated with it */
    has(key: string): boolean;
    /** all keys with at least one value */
    keys(): Iterable<string>;
    /**
     * iterate over all values
     *
     * If a key has multiple values they will be joined by `delimiter`.
     */
    values(delimiter?: string): IterableIterator<string>;
    /** iterate over all values added */
    valuesAll(): IterableIterator<string>;
}
export declare class Headers implements MhtmlHeaders {
    #private;
    [Symbol.iterator](): Iterator<[string, string]>;
    append(key: string, value: string): void;
    entries(delim?: string): IterableIterator<[string, string]>;
    entriesAll(): IterableIterator<[string, string]>;
    get(key: string, delim?: string): string | null;
    getAll(key: string): string[];
    has(key: string): boolean;
    keys(): IterableIterator<string>;
    values(delim?: string): IterableIterator<string>;
    valuesAll(): IterableIterator<string>;
}