Add SMTP as example with 2 experimental features

Author: Dreksh

examples/smtp_example/.bazelrc

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+# Import Shared settings
+import %workspace%/../../shared.bazelrc
+
+# Import CI settings.
+import %workspace%/../../ci.bazelrc
+
+# Try to import a local.rc file; typically, written by CI
+try-import %workspace%/../../local.bazelrc

examples/smtp_example/BUILD.bazel

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+load("@bazel_gazelle//:def.bzl", "gazelle", "gazelle_binary")
+load("@build_bazel_rules_swift//swift:swift.bzl", "swift_binary")
+load("@cgrindel_bazel_starlib//bzltidy:defs.bzl", "tidy")
+load("@rules_swift_package_manager//swiftpkg:defs.bzl", "swift_update_packages")
+
+tidy(
+    name = "tidy",
+    targets = [
+        ":swift_update_pkgs",
+        ":update_build_files",
+    ],
+)
+
+# MARK: - Gazelle
+
+# Ignore the Swift build folder
+# gazelle:exclude .build
+
+gazelle_binary(
+    name = "gazelle_bin",
+    languages = [
+        "@bazel_skylib_gazelle_plugin//bzl",
+        "@rules_swift_package_manager//gazelle",
+    ],
+)
+
+gazelle(
+    name = "update_build_files",
+    gazelle = ":gazelle_bin",
+)
+
+swift_update_packages(
+    name = "swift_update_pkgs",
+    gazelle = ":gazelle_bin",
+    generate_swift_deps_for_workspace = False,
+    update_bzlmod_stanzas = True,
+)
+
+swift_binary(
+    name = "smtp_example",
+    srcs = ["main.swift"],
+    module_name = "smtp_example",
+    visibility = ["//visibility:public"],
+    deps = ["@swiftpkg_swift_smtp//:SwiftSMTP"],
+)

examples/smtp_example/MODULE.bazel

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+bazel_dep(
+    name = "rules_swift_package_manager",
+    version = "0.0.0",
+)
+local_path_override(
+    module_name = "rules_swift_package_manager",
+    path = "../..",
+)
+
+bazel_dep(name = "cgrindel_bazel_starlib", version = "0.20.2")
+bazel_dep(name = "bazel_skylib", version = "1.6.0")
+bazel_dep(name = "apple_support", version = "1.9.0", repo_name = "build_bazel_apple_support")
+bazel_dep(
+    name = "rules_swift",
+    version = "1.18.0",
+    repo_name = "build_bazel_rules_swift",
+)
+bazel_dep(
+    name = "rules_apple",
+    version = "3.5.1",
+    repo_name = "build_bazel_rules_apple",
+)
+
+bazel_dep(
+    name = "bazel_skylib_gazelle_plugin",
+    version = "1.6.0",
+    dev_dependency = True,
+)
+bazel_dep(
+    name = "gazelle",
+    version = "0.36.0",
+    dev_dependency = True,
+    repo_name = "bazel_gazelle",
+)
+# swift_deps START
+swift_deps = use_extension(
+    "@rules_swift_package_manager//:extensions.bzl",
+    "swift_deps",
+)
+swift_deps.from_file(
+    deps_index = "//:swift_deps_index.json",
+)
+use_repo(
+    swift_deps,
+    "swiftpkg_swift_smtp",
+)
+# swift_deps END

examples/smtp_example/Package.resolved

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+// swift-tools-version: 5.7
+
+import PackageDescription
+
+let package = Package(
+    name: "smtp_example",
+    dependencies: [
+        .package(url: "https://github.com/sersoft-gmbh/swift-smtp", from: "2.10.0"),
+    ]
+)

examples/smtp_example/Package.swift

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+# smtp Example

examples/smtp_example/README.md

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+# Intentionally blank: Using bzlmod

examples/smtp_example/WORKSPACE

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+# Intentionally blank: Force bzlmod to strict mode

examples/smtp_example/WORKSPACE.bzlmod

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+#!/usr/bin/env bash
+
+set -o errexit -o nounset -o pipefail
+
+# Use the Bazel binary specified by the integration test. Otherise, fall back 
+# to bazel.
+bazel="${BIT_BAZEL_BINARY:-bazel}"
+
+# Generate Swift external deps and update build files
+"${bazel}" run //:tidy
+
+# Ensure that it builds and tests pass
+"${bazel}" test //...

examples/smtp_example/do_test

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+import SwiftSMTP
+
+let configuration = Configuration.fromEnvironment()
+print(configuration.server.hostname)