code: func NewDecoder(r io.Reader) *Decoder {
  	d := &Decoder{
  		ns:       make(map[string]string),
  		nextByte: -1,
  		line:     1,
  		Strict:   true,
  	}
  	d.switchToReader(r)
  	return d
  }
docs: // NewDecoder creates a new XML parser reading from r.
  // If r does not implement io.ByteReader, NewDecoder will
  // do its own buffering.