partEncryptionKey := objectEncryptionKey.DerivePartKey(uint32(partID))
			in := io.Reader(hashReader)
			if size > encryptBufferThreshold {
				// The encryption reads in blocks of 64KB.
				// We add a buffer on bigger files to reduce the number of syscalls upstream.
				in = bufio.NewReaderSize(hashReader, encryptBufferSize)
			}

			var nonce [12]byte
			tmp := sha256.Sum256(fmt.Append(nil, uploadID, partID))

	}

	objAPI := api.ObjectAPI()
	if objAPI == nil {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrServerNotInitialized), r.URL)
		return
	}

	// Tags XML will not be bigger than 1MiB in size, fail if its bigger.
	tags, err := tags.ParseObjectXML(io.LimitReader(r.Body, 1<<20))
	if err != nil {
		writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}