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: client.rs
    path of file: ./repos/rivet/lib/smithy-output/api-group/rust/rust/src
    
    the code of the file until where you have to start completion: // Code generated by software.amazon.smithy.rust.codeg
    
/// fn base() -> ServiceBuilder<AwsMiddlewareStack> {
///     let credential_provider = AsyncMapRequestLayer::for_mapper(CredentialsStage::new());
///     let signer = MapRequestLayer::for_mapper(SigV4SigningStage::new(SigV4Signer::new()));
///     let endpoint_resolver = MapRequestLayer::for_mapper(AwsEndpointStage);
///     let user_agent = MapRequestLayer::for_mapper(UserAgentStage::new());
///     let recursion_detection = MapRequestLayer::for_mapper(RecursionDetectionStage::new());
///     // These layers can be considered as occurring in order, that is:
///     // 1. Resolve an endpoint
///     // 2. Add a user agent
///     // 3. Acquire credentials
///     // 4. Sign with credentials
///     // (5. Dispatch over the wire)
///     ServiceBuilder::new()
///         .layer(endpoint_resolver)
///         .layer(user_agent)
///         .layer(credential_provider)
///         .layer(signer)
///         .layer(recursion_detection)
/// }