func (r *Reader) ReadFloat64() float64 {
	if r.err != nil {
		return 0
	}
	var n int
	n, r.err = io.ReadFull(r.rd, r.b[:8])
	r.cnt += n
	if r.err != nil {
		return 0
	}
	bits := binary.LittleEndian.Uint64(r.b[:8])
	return math.Float64frombits(bits)
}
func (r *Reader) ReadFloat64() float64 {
	if r.err != nil {
		return 0
	}
	var n int
	n, r.err = io.ReadFull(r.rd, r.b[:8])
	r.cnt += n
	if r.err != nil {
		return 0
	}
	bits := binary.LittleEndian.Uint64(r.b[:8])
	return math.Float64frombits(bits)
}
// ReadFloat64 reads and returns a float64.