code: func (r *RewriteOptions) blobFn() BlobRewriteFn {
  	if r.BlobFn == nil {
  		return noopBlobFn
  	}
  	return r.BlobFn
  }
docs: // blobFn returns a useable BlobRewriteFn, either the one that was given in the
  // *RewriteOptions, or a noopBlobFn.