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: engine_headless.rs
    path of file: ./repos/wasmer/examples
    
    the code of the file until where you have to start completion: //! Defining an engine in Wasmer is one of the fundame
    
fn main() -> Result<(), Box<dyn std::error::Error>> {
    // First step, let's compile the Wasm module and serialize it.
    // Note: we need a compiler here.
    let serialized_module_file = {
        // Let's declare the Wasm module with the text representation.
        let wasm_bytes = wat2wasm(
            r#"
(module
  (type $sum_t (func (param i32 i32) (result i32)))
  (func $sum_f (type $sum_t) (param $x i32) (param $y i32) (result i32)
    local.get $x
    local.get $y
    i32.add)
  (export "sum" (func $sum_f)))
"#
            .as_bytes(),
        )?;

        // Define a compiler configuration.
        //
        // In this situation, the compiler is
        // `wasmer_compiler_cranelift`. The compiler is responsible to
        // compile the Wasm module into executable code.
        let compiler = Cranelift::default();

        // Create a store, that holds the engine.
        let store = Store::new(compiler);

        println!("Compiling module...");
        // Let's compile the Wasm module.
        let module = Module::new(&store, wasm_bytes)?;

        println!("Serializing module...");
        // Here we go. Let's serialize the compiled Wasm module in a
        // file.
        let serialized_module_file = NamedTempFile::new()?;
        module.serialize_to_file(&serialized_module_file)?;

        serialized_module_file
    };

    // Second step, deserialize the compiled Wasm module, and execute
    // it, for example with Wasmer without a compiler.
    {
        println!("Creating headless Universal engine...");
        // We create a headless Universal engine.
        let engine = EngineBuilder::headless();
        let mut store = Store::new(engine);

        println!("Deserializing module...");
        // Here we go.
        //
        // Deserialize the compiled Wasm module. This code is unsafe
        // because Wasmer can't assert the bytes are valid (see the
        // `wasmer::Module::deserialize`'s documentation to learn
        // more).
        let module = unsafe { Module::deserialize_from_file(&store, serialized_module_file) }?;

        // Congrats, the Wasm module has been deserialized! Now let's
        // execute it for the sake of having a complete example.

        // Create an import object. Since our Wasm module didn't declare
        // any imports, it's an empty object.
        let import_object = imports! {};

        println!("Instantiating module...");
        // Let's instantiate the Wasm module.
        let instance = Instance::new(&mut store, &module, &import_object)?;

        println!("Calling `sum` function...");
        // The Wasm module exports a function called `sum`.
        let sum = instance.exports.get_function("sum")?;
        let results = sum.call(&mut store, &[Value::I32(1), Value::I32(2)])?;

        println!("Results: {:?}", results);
        assert_eq!(results.to_vec(), vec![Value::I32(3)]);
    }

    Ok(())
}