func Int64ToBytesTo(v int64, ret []byte) {
	ret[0] = byte(v >> 56)
	ret[1] = byte(v >> 48)
	ret[2] = byte(v >> 40)
	ret[3] = byte(v >> 32)
	ret[4] = byte(v >> 24)
	ret[5] = byte(v >> 16)
	ret[6] = byte(v >> 8)
	ret[7] = byte(v)
}
Int64ToBytesTo int64 value to bytes array using big order
package goetty
import (
	"errors"
	"io"
)
func ReadN(r io.Reader, n int) ([]byte, error) {
	data := make([]byte, n)
	_, err := r.Read(data)
	if err != nil {
		return nil, err
	}
	return data, nil
}
func ReadInt(r io.Reader) (int, error) {
	data, err := ReadN(r, 4)
	if err != nil {
		return 0, err
	}
	return Byte2Int(data), nil
}
func Byte2Int(data []byte) int {
	return int((int(data[0])&0xff)<<24 | (int(data[1])&0xff)<<16 | (int(data[2])&0xff)<<8 | (int(data[3]) & 0xff))
}
func Byte2Int64(data []byte) int64 {
	return int64((int64(data[0])&0xff)<<56 | (int64(data[1])&0xff)<<48 | (int64(data[2])&0xff)<<40 | (int64(data[3])&0xff)<<32 | (int64(data[4])&0xff)<<24 | (int64(data[5])&0xff)<<16 | (int64(data[6])&0xff)<<8 | (int64(data[7]) & 0xff))
}
func Int2BytesTo(v int, ret []byte) {
	ret[0] = byte(v >> 24)
	ret[1] = byte(v >> 16)
	ret[2] = byte(v >> 8)
	ret[3] = byte(v)
}
func Int2Bytes(v int) []byte {
	ret := make([]byte, 4)
	Int2BytesTo(v, ret)
	return ret
}