code: func NewWriter(w io.Writer) *Writer {
  	return &Writer{
  		raw:  w,
  		zlib: zlib.NewWriter(w),
  	}
  }
docs: // NewWriter returns a new Writer writing to w.
  //
  // The returned Writer implements io.WriteCloser. Close should be called when
  // finished with the Writer. Close will not close the underlying io.Writer.