// Verify that checksums of staleDisks
			// match expected values
			for i := range staleWriters {
				if staleWriters[i] == nil {
					continue
				}
				if !bytes.Equal(bitrotWriterSum(staleWriters[i]), bitrotWriterSum(writers[i])) {
					t.Errorf("Test %d: heal returned different bitrot checksums", i)
				}
			}
		}
	}

		}
		if bw, ok := w.(io.Closer); ok {
			errs[i] = bw.Close()
		} else {
			errs[i] = nil
		}
	}
	return errs
}

// Returns hash sum for whole-bitrot, nil for streaming-bitrot.
func bitrotWriterSum(w io.Writer) []byte {
	if bw, ok := w.(*wholeBitrotWriter); ok {
		return bw.Sum(nil)
	}
	return nil
}

// Returns the size of the file with bitrot protection