import { InputBag } from './input-bag.js';
export declare class RequestHeaderBag<RequestHeaders> extends InputBag<RequestHeaders> {
    /**
     * Returns the lowercased string value for the given `name`.
     */
    private lowercase;
    /**
     * Returns the input value for the given `name`. Returns `undefined`
     * if the given `name` does not exist in the input bag.
     */
    get<Key extends keyof RequestHeaders>(key: Key, defaultValue?: RequestHeaders[Key]): RequestHeaders[Key];
    get<Key extends keyof RequestHeaders>(key: Key, defaultValue: RequestHeaders[Key]): NonNullable<RequestHeaders[Key]>;
    /**
     * Set an input for the given `name` and assign the `value`. This
     * overrides a possibly existing input with the same `name`.
     */
    set<Key extends keyof RequestHeaders>(key: Key | Partial<RequestHeaders>, value?: any): this;
    /**
     * Removes the input with the given `name`.
     */
    remove<Key extends keyof RequestHeaders>(key: Key): this;
}