import { Effect, Stream } from "effect"; export const toReadableByteStream = <E>(  source: Stream.Stream<string, E>,): ReadableStream<Uint8Array> => {  const encoder = new TextEncoder();  return Stream.toReadableStream(Stream.map(source, (value) => encoder.encode(value)));}; const abortEffect = (signal: AbortSignal): Effect.Effect<void> =>  Effect.callback<void>((resume) => {    const abort = (): void => resume(Effect.void);    if (signal.aborted) {      abort();      return Effect.void;    }    signal.addEventListener("abort", abort, { once: true });    return Effect.sync(() => signal.removeEventListener("abort", abort));  }); export const withSseHeartbeat = <E, R>(  frames: Stream.Stream<string, E, R>,  intervalMs: number,  signal?: AbortSignal,): Stream.Stream<string, E, R> => {  const heartbeat: Stream.Stream<string> = Stream.map(    Stream.tick(intervalMs),    () => ": keepalive\n\n",  );  const stream: Stream.Stream<string, E, R> = Stream.merge(frames, heartbeat, {    haltStrategy: "left",  });  return signal ? stream.pipe(Stream.interruptWhen(abortEffect(signal))) : stream;}; export const buildSseHeaders = (extra: Record<string, string> = {}): Record<string, string> => ({  "Content-Type": "text/event-stream",  "Cache-Control": "no-cache, no-transform",  Connection: "keep-alive",  "X-Accel-Buffering": "no",  ...extra,});