code: func (d *digest) Reset() {
  	copy(d.h[:], d.ih[:])
  	d.t[0] = 0
  	d.t[1] = 0
  	d.f[0] = 0
  	d.f[1] = 0
  	d.nx = 0
  	if d.isKeyed {
  		d.Write(d.paddedKey[:])
  	}
  }
docs: // Reset resets the state of digest to the initial state
  // after configuration and keying.