Swift: Add HTTP configuration example (#7421)

* Add HTTP config example - checkpoint

* Finished example.

Author: shepazon

swift/example_code/swift-sdk/http-config/Package.swift

@@ -0,0 +1,47 @@
+// swift-tools-version: 5.9
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+//
+// (swift-tools-version has two lines here because it needs to be the first
+// line in the file, but it should also appear in the snippet below)
+//
+// snippet-start:[swift.cognito-identity-provider.scenario.package]
+// swift-tools-version: 5.9
+//
+// The swift-tools-version declares the minimum version of Swift required to
+// build this package.
+
+import PackageDescription
+
+let package = Package(
+    name: "http-config",
+    // Let Xcode know the minimum Apple platforms supported.
+    platforms: [
+        .macOS(.v13),
+        .iOS(.v15)
+    ],
+    dependencies: [
+        // Dependencies declare other packages that this package depends on.
+        .package(
+            url: "https://github.com/awslabs/aws-sdk-swift",
+            from: "1.0.0"),
+        .package(
+            url: "https://github.com/apple/swift-argument-parser.git",
+            branch: "main"
+        )
+    ],
+    targets: [
+        // Targets are the basic building blocks of a package, defining a module or a test suite.
+        // Targets can depend on other targets in this package and products
+        // from dependencies.
+        .executableTarget(
+            name: "cognito-scenario",
+            dependencies: [
+                .product(name: "AWSS3", package: "aws-sdk-swift"),
+                .product(name: "ArgumentParser", package: "swift-argument-parser")
+            ],
+            path: "Sources")
+
+    ]
+)
+// snippet-end:[swift.cognito-identity-provider.scenario.package]

swift/example_code/swift-sdk/http-config/Sources/entry.swift

@@ -0,0 +1,88 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+//
+// snippet-start:[swift.http-config]
+// An example demonstrating how to customize the configuration of the HTTP
+// client used by an Amazon Web Services (AWS) service client.
+
+import ArgumentParser
+// snippet-start:[swift.http-config.imports]
+import ClientRuntime
+import AWSS3
+import SmithyHTTPAPI
+import AwsCommonRuntimeKit
+// snippet-end:[swift.http-config.imports]
+
+struct ExampleCommand: ParsableCommand {
+    @Option(help: "Name of the Amazon Region to use")
+    var region = "us-east-1"
+
+    static var configuration = CommandConfiguration(
+        commandName: "http-config",
+        abstract: """
+        Demonstrates how to configure the HTTP client used by an AWS service client.
+        """,
+        discussion: """
+        """
+    )
+
+    /// Called by ``main()`` to run the bulk of the example.
+    func runAsync() async throws {
+        // snippet-start:[swift.http-config.headers]
+        let config = try await S3Client.S3ClientConfiguration(
+            region: region,
+            httpClientConfiguration: HttpClientConfiguration(
+                defaultHeaders: Headers(
+                    [
+                        "X-My-Custom-Header": "CustomHeaderValue",
+                        "X-Another-Custom-Header": "AnotherCustomValue"
+                    ]
+                )
+            )
+        )
+        let s3Client = S3Client(config: config)
+        // snippet-end:[swift.http-config.headers]
+
+        print("*** Getting list of buckets...")
+        _ = try await s3Client.listBuckets(input: ListBucketsInput())
+        print("*** Success!\n")
+
+        print("*** Getting bucket list with custom timeouts...")
+        
+        // snippet-start: [swift.http-config.timeouts]
+        do {
+            let config = try await S3Client.S3ClientConfiguration(
+                region: region,
+                httpClientConfiguration: HttpClientConfiguration(
+                    connectTimeout: 2,
+                    socketTimeout: 5
+                )
+            )
+            let s3Client = S3Client(config: config)
+            _ = try await s3Client.listBuckets(input: ListBucketsInput())
+            print("*** Success!")
+        } catch CommonRunTimeError.crtError(let crtError) {
+            print("*** An error occurred accessing the bucket list: \(crtError.message)")
+        } catch {
+            print("*** Unexpected error occurred requesting the bucket list.")
+        }
+        // snippet-end: [swift.http-config.timeouts]
+
+    }
+}
+
+/// The program's asynchronous entry point.
+@main
+struct Main {
+    static func main() async {
+        let args = Array(CommandLine.arguments.dropFirst())
+
+        do {
+            let command = try ExampleCommand.parse(args)
+            try await command.runAsync()
+        } catch {
+            ExampleCommand.exit(withError: error)
+        }
+    }    
+}
+// snippet-end:[swift.http-config]