message: Do not throw error on duplication detected, just truncate
  to prevent mixing up the duplicated file contents
diff: @@ -77,14 +77,9 @@ export default class Writer {
  await ensureDir(dirname(filename));
  const file = await Deno.open(filename, { write: true, create: true });
  - await Deno.flock(file.rid);
  try {
  - // Prevent overwriting (often happens on case-insensitive file systems)
  - const stat = await file.stat();
  - if (stat.size !== 0) {
  - throw new Error(`File '${filename}' already exists.`);
  - }
  -
  + await Deno.flock(file.rid);
  + await file.truncate();
  const contentStream = page.content instanceof Uint8Array
  ? page.content
  : new TextEncoder().encode(page.content);
  