R2 Bucket File multichunk upload doesn't work.

const chunk = await request.arrayBuffer();
const multipartUpload = env.BRIEFLI_PUBLIC_FILES.resumeMultipartUpload(key, uploadId);
const chunkUint8Array = new Uint8Array(chunk);
const uploadedPart: R2UploadedPart = await multipartUpload.uploadPart(partNumber, chunkUint8Array);