- attach.UploadWriterOptions (was the unexported uploadWriterOptions) gives
code that writes an upload to the bucket itself the same Content-Type and
Content-Disposition: attachment for non-inline types that attach.Store stores
- writeBlob calls it; Store behaviour unchanged
- TestUploadWriterOptions table test
- lagoon README, docs/database/attachments.md and docs/services/storage.md
describe it for writers that bypass attach.Store