n, err := r.src.Read(p)
	r.bytesRead += int64(n)
	if r.sha256 != nil {
		r.sha256.Write(p[:n])
	}
	if r.contentHasher != nil {
		r.contentHasher.Write(p[:n])
	}

	if err == io.EOF { // Verify content SHA256, if set.
		if r.expectedMin > 0 {
			if r.bytesRead < r.expectedMin {
				return 0, SizeTooSmall{Want: r.expectedMin, Got: r.bytesRead}
			}
		}
		if r.expectedMax > 0 {

			Tagger: t,
		}
	}
	return wrapReader{
		Reader: wrapped,
	}
}

// A Reader wraps an io.Reader and computes the
// MD5 checksum of the read content as ETag.
//
// Optionally, a Reader can also verify that
// the computed ETag matches an expected value.
// Therefore, it compares both ETags once the
// underlying io.Reader returns io.EOF.
// If the computed ETag does not match the