Android support and CI

Author: marcprux

.github/workflows/main.yml

@@ -26,3 +26,8 @@ jobs:
     uses: apple/swift-nio/.github/workflows/macos_tests.yml@main
     with:
       build_scheme: swift-openapi-urlsession
+
+  android-tests:
+    name: Android tests
+    uses: skiptools/swift-android-action@v2
+

Sources/OpenAPIURLSession/BufferedStream/Lock.swift

@@ -28,6 +28,8 @@
 
 #if canImport(Darwin)
 import Darwin
+#elseif canImport(Android)
+import Android
 #elseif canImport(Glibc)
 import Glibc
 #endif