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: assume_role.rs
    path of file: ./repos/aws-sdk-rust/sdk/aws-config/src/sts
    
    the code of the file until where you have to start completion: /*
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: Apache-2.0
 */

//! Assume credentials for a role through the AWS Security Token Service (STS).

use aws_credential_types::provider::{
    self, error::CredentialsError, future, ProvideCredentials, SharedCredentialsProvider,
};
use aws_sdk_sts::operation::assume_role::builders::AssumeRoleFluentBuilder;
use aws_sdk_sts::operation::assume_role::AssumeRoleError;
use aws_sdk_sts::types::PolicyDescriptorType;
use aws_sdk_sts::Client as StsClient;
use aws_smithy_runtime::client::identity::IdentityCache;
use aws_smithy_runtime_api::client::result::SdkError;
use aws_smithy_types::error::display::DisplayErrorContext;
use aws_types::region::Region;
use aws_types::SdkConfig;
use std::time::Duration;
use tracing::Instrument;

/// Credentials provider that uses credential
    
    async fn build_method_from_sdk_config() {
        let _guard = capture_test_logs();
        let (http_client, request) = capture_request(Some(
            http::Response::builder()
                .status(404)
                .body(SdkBody::from(""))
                .unwrap(),
        ));
        let conf = crate::defaults(BehaviorVersion::latest())
            .env(Env::from_slice(&[
                ("AWS_ACCESS_KEY_ID", "123-key"),
                ("AWS_SECRET_ACCESS_KEY", "456"),
                ("AWS_REGION", "us-west-17"),
            ]))
            .use_dual_stack(true)
            .use_fips(true)
            .time_source(StaticTimeSource::from_secs(1234567890))
            .http_client(http_client)
            .load()
            .await;
        let provider = AssumeRoleProvider::builder("role")
            .configure(&conf)
            .build()
            .await;
        let _ = dbg!(provider.provide_credentials().await);
        let req = request.expect_request();
        let auth_header = req.headers().get(AUTHORIZATION).unwrap().to_string();
        let expect = "Credential=123-key/20090213/us-west-17/sts/aws4_request";
        assert!(
            auth_header.contains(expect),
            "Expected header to contain {expect} but it was {auth_header}"
        );
        // ensure that FIPS & DualStack are also respected
        assert_eq!("https://sts-fips.us-west-17.api.aws/", req.uri())
    }