file-type sniffer should never work on more than 8KiB

[lidel]

Ref. https://www.npmjs.com/package/file-type#usage – we should be fine with reading only the magic bytes at the beginning of the file.

file-type can sometimes work with as few as 4 bytes (e.g., for PNGs), some formats (like ISO files) need up to 4100 bytes. A buffer of 8KB (8192 bytes) is probably the ceiling on how much data should we wait for before being able to do the sniffing, passing anything more than that

Right now, the amount of passed data depends on codec-specific plugin. For dag-pb we seem to pass entire block, so the amount of data passed is way to high 256KiB up to 1MiB:

• helia-verified-fetch/packages/verified-fetch/src/plugins/plugin-handle-dag-pb.ts

  Line 158 in c36970d

  await handleServerTiming('set-content-type', '', async () => setContentType({ bytes: firstChunk, path, response, contentTypeParser, log }), withServerTiming)