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: variant.rs
    path of file: ./repos/ntex/ntex-util/src/services
    
    the code of the file until where you have to start completion: //! Contains `Variant` service and related types and functions.
use std::{fmt, marker::PhantomData, task::Context, task::Poll};

use ntex_service::{IntoServiceFactory, Service, ServiceCtx, ServiceFactory};

/// Construct `Variant` service factory.
///
/// Variant service allow to combine multiple different services into a single service.
pub fn variant<V1: ServiceFactory<V1R, V1C>, V1R, V1C>(
    facto
    
    async fn test_variant() {
        let factory = variant(fn_factory(|| async { Ok::<_, ()>(Srv1) }))
            .v2(fn_factory(|| async { Ok::<_, ()>(Srv2) }))
            .clone()
            .v3(fn_factory(|| async { Ok::<_, ()>(Srv2) }))
            .clone();
        let service = factory.pipeline(&()).await.unwrap().clone();

        assert!(lazy(|cx| service.poll_ready(cx)).await.is_ready());
        assert!(lazy(|cx| service.poll_shutdown(cx)).await.is_ready());

        assert_eq!(service.call(Variant3::V1(())).await, Ok(1));
        assert_eq!(service.call(Variant3::V2(())).await, Ok(2));
        assert_eq!(service.call(Variant3::V3(())).await, Ok(2));
    }