golang integer to byte array and byte array to integer function

IntToByteArray.go

package main

import (
	"fmt"
	"unsafe"
)

func main(){
    // integer for convert
    num := int64(1354321354812)
    fmt.Println("Original number:", num)
	
    // integer to byte array
    byteArr := IntToByteArray(num)
    fmt.Println("Byte Array", byteArr)
	
    // byte array to integer again
    numAgain := ByteArrayToInt(byteArr)
    fmt.Println("Converted number:", numAgain)
}

func IntToByteArray(num int64) []byte {
    size := int(unsafe.Sizeof(num))
    arr := make([]byte, size)
    for i := 0 ; i < size ; i++ {
        byt := *(*uint8)(unsafe.Pointer(uintptr(unsafe.Pointer(&num)) + uintptr(i)))
        arr[i] = byt
    }
    return arr
}

func ByteArrayToInt(arr []byte) int64{
    val := int64(0)
    size := len(arr)
    for i := 0 ; i < size ; i++ {
        *(*uint8)(unsafe.Pointer(uintptr(unsafe.Pointer(&val)) + uintptr(i))) = arr[i]
    }
    return val
}