Function drainStdio

apps/kimi-code/src/cli/headless-exit.ts:63–77

(
  streams: readonly Writable[],
  timeoutMs: number = HEADLESS_STDIO_DRAIN_TIMEOUT_MS,
)

 * wait is bounded so a permanently-stuck consumer can't re-introduce the hang.
 */
export async function drainStdio(
  streams: readonly Writable[],
  timeoutMs: number = HEADLESS_STDIO_DRAIN_TIMEOUT_MS,
): Promise<void> {
  let timer: NodeJS.Timeout | undefined;
  const timeout = new Promise<void>((resolve) => {
    timer = setTimeout(resolve, timeoutMs);
    timer.unref?.();
  });
  try {
    await Promise.race([Promise.all(streams.map(flushStream)).then(() => undefined), timeout]);
  } finally {
    if (timer !== undefined) clearTimeout(timer);
  }
}

/**
 * Finalize a completed headless run: flush stdio, then arm the force-exit