export type SseFrame<T = unknown, E extends string | undefined = string | undefined> = {
    data: T;
    event?: E;
};
export type SseErrorFrame = SseFrame<Error, "error" | undefined>;
export declare function toSseStream(src: ReadableStream<SseFrame>, options?: {
    onDone?: (status: number, reason?: unknown) => void;
    toError?: (error: unknown) => unknown;
    keepAliveMs?: number;
}): ReadableStream<Uint8Array>;