func (r *Reader) ETag() ETag {
	sum := r.md5.Sum(nil)
	return ETag(sum)
}

// VerifyError is an error signaling that a
// computed ETag does not match an expected
// ETag.
type VerifyError struct {
	Expected ETag
	Computed ETag
}

func (v VerifyError) Error() string {
	return fmt.Sprintf("etag: expected ETag %q does not match computed ETag %q", v.Expected, v.Computed)
}

	// assert the http response status code.
	verifyError(c, response, "AccessDenied", "Access Denied.", http.StatusForbidden)

	// initiate anonymous HTTP request to fetch the object which does exist. We need to return AccessDenied.
	response, err = s.client.Get(getGetObjectURL(s.endPoint, bucketName, objectName))
	c.Assert(err, nil)
	// assert the http response status code.

					Want: r.contentHash.Encoded,
					Got:  base64.StdEncoding.EncodeToString(sum),
				}
				return n, err
			}
		}
	}
	if err != nil && err != io.EOF {
		if v, ok := err.(etag.VerifyError); ok {
			return n, BadDigest{
				ExpectedMD5:   v.Expected.String(),
				CalculatedMD5: v.Computed.String(),
			}
		}
	}
	return n, err
}