// MD5 checksum of everything it reads as ETag.
//
// It also computes the SHA256 checksum of everything it reads
// if sha256Hex is not the empty string.
//
// If size resp. actualSize is unknown at the time of calling
// NewReader then it should be set to -1.
// When size is >=0 it *must* match the amount of data provided by r.
//
// NewReader may try merge the given size, MD5 and SHA256 values

				Computed: etag,
			}
		}
	}
	return n, err
}

// ETag returns the ETag of all the content read
// so far. Reading more content changes the MD5
// checksum. Therefore, calling ETag multiple
// times may return different results.
func (r *Reader) ETag() ETag {
	sum := r.md5.Sum(nil)
	return ETag(sum)
}

// VerifyError is an error signaling that a