/**
 * Represents the body of an incoming HTTP request.
 * Provides accessors for JSON, text, Buffer, Blob, and URLSearchParams representations.
 *
 * @template Json expected JSON type (default `any`).
 */
export default class IncomingBody<Json = any> {
    #private;
    /** Size of the body in bytes. */
    readonly size: number;
    /**
     * Constructs an IncomingBody instance.
     *
     * @param buffer original body content. Can be a Buffer, string, object, or null.
     * Objects will be converted into strings.
     */
    constructor(buffer: Buffer | string | object | null);
    /**
     * Parses and returns the body as JSON.
     * Caches parsed value for future calls.
     *
     * @template T type to parse into when `Json` generic is not a record.
     * @template N whether the result should be non-nullable.
     * @template R resolved return type based on `Json` and `T`.
     * @param nonNullable if `true`, enforces non-nullability in parsing.
     * @returns parsed JSON of type `R` or `null` if parsing fails and `nonNullable` is `false`.
     */
    json<T extends Record<string, any> = Record<string, any>, N extends boolean = false, R = Json extends Record<any, any> ? Json : T>(nonNullable?: N): N extends true ? R : (R | null);
    /**
     * Returns the body decoded as a UTF-8 string.
     * Caches the result for future calls.
     *
     * @returns body text.
     */
    text(): string;
    /**
     * Returns the raw Buffer of the body.
     *
     * @returns body Buffer.
     */
    buffer(): Buffer;
    /**
     * Returns the body as a Blob with the specified MIME type.
     * Caches the result for future calls.
     *
     * @param mimeType MIME type for the Blob (e.g., "application/json").
     * @returns blob representing the body.
     */
    blob(mimeType: string): Blob;
    /**
     * Parses the body as URL search parameters.
     * Caches the result for future calls.
     *
     * @returns URLSearchParams instance built from the body string.
     */
    urlSearchParams(): URLSearchParams;
}