Write struct to file

[Chopin]

Hello!

import std.stdio;
struct nagger
{
    string name;
    int age;
    double weight;
    string msg;
}

void main()
{
    auto lal = new nagger();
    lal.name = "AHAHAHAHHA";
    lal.age = 23;
    lal.weight = 108.5;
    lal.msg = "fgfdgfdgfdgfdgfdgfdg";
    writeln(cast(ubyte[])(lal));
}

Gives error: Error: e2ir: cannot cast lal of type nagger* to type 
ubyte[]
I have bad knowledge about this and don't understand why I cant 
do this :(
What I really want is an array of naggers and save them binary to 
a file :)
This was like my step 1, and it failed miserably...

Thanks for help.