Cast struct to byte

Hi,

I am trying to send a struct via a UdpClient class. The Send method
expects a byte array, which a struct certainly is, but I am not sure
how to write the type cast operator.

public struct SomePacket
{
public int someData;

public static explicit operator byte[]( SomePacket packet )
{
???
}
}

I'm not even sure if this is possible, since a byte array is a
reference type, and a struct is a value type.

Thanks,
-Aleko