You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: windows_guid.rs
    path of file: ./repos/uuid/examples/src
    
    the code of the file until where you have to start completion: //! Converting between Windows GUIDs and UUIDs.
//!
//! Windows GUIDs are specified as using mixed endianness.
//! What you get will depend on the source of the GUID.
//! Functions like `CoCreateGuid` will generate a valid UUID so
//! the fields will be naturally ordered for `Uuid::from_fields`.
//! Other GUIDs might need 
    
fn uuid_from_cocreateguid() {
    use uuid::{Uuid, Variant, Version};
    use windows_sys::core;
    use windows_sys::Win32::System::Com::CoCreateGuid;

    let mut guid = core::GUID {
        data1: 0,
        data2: 0,
        data3: 0,
        data4: [0u8; 8],
    };

    unsafe {
        CoCreateGuid(&mut guid);
    }

    let uuid = Uuid::from_fields(guid.data1, guid.data2, guid.data3, &guid.data4);

    assert_eq!(Variant::RFC4122, uuid.get_variant());
    assert_eq!(Some(Version::Random), uuid.get_version());
}