writer.go
func (z *Writer) Reset(w io.Writer) {
	z.Header = Header{}
	z.dst = w
	z.checksum.Reset()
	z.zdata = z.zdata[:0]
	z.data = z.data[:0]
	z.idx = 0
}
func (z *Writer) Reset(w io.Writer) {
	z.Header = Header{}
	z.dst = w
	z.checksum.Reset()
	z.zdata = z.zdata[:0]
	z.data = z.data[:0]
	z.idx = 0
}
// Reset clears the state of the Writer z such that it is equivalent to its
// initial state from NewWriter, but instead writing to w.
// No access to the underlying io.Writer is performed.