Merge branch 'main' into allow-download-triggered-pipeline

docs/preview-apis.md

@@ -0,0 +1,72 @@
+# Preview APIs
+
+The APIs listed here are currently marked as preview APIs, and as such may
+change in the future (we don't guarante binary or source compatibility between
+releases for these APIs).
+
+We've marked these APIs using the [Experimental][1] attribute, which means
+that compilation error will be shown if they're used:
+
+> error APL0001: 'PreviewAPI' is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+
+This means that it's not possible to use these preview APIs by accident, the diagnostic has to be explicitly ignored.
+
+Example program consuming preview API:
+
+```cs
+using System.Diagnostics.CodeAnalysis;
+
+class App
+{
+    public static void Main ()
+    {
+        Do.Something ();
+    }
+}
+
+[Experimental ("APL0001")]
+class Do {
+    public static void Something () {}
+}
+```
+
+this will show:
+
+> Program.cs(8,9): error APL0001: 'Do' is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+
+Then ignore the warning in order to make the code compile:
+
+```cs
+using System.Diagnostics.CodeAnalysis;
+
+class App
+{
+    public unsafe static void Main ()
+    {
+        #pragma warning disable APL0001
+        Do.Something ();
+        #pragma warning restore APL0001
+    }
+}
+
+[Experimental ("APL0001")]
+class Do {
+    public static void Something () {}
+}
+
+```
+
+Our diagnostic IDs will be of the format `APL####` - for instance `APL0001` -
+where the number is just monotonically increasing since the previous number,
+without any specific meaning.
+
+References:
+
+* https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.codeanalysis.experimentalattribute?view=net-8.0
+* https://learn.microsoft.com/en-us/dotnet/fundamentals/apicompat/preview-apis#experimentalattribute
+
+## Placeholder header for APL####
+
+Coming soon!
+
+[1]: https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.codeanalysis.experimentalattribute?view=net-8.0

src/Foundation/NSUrlSessionHandler.cs

@@ -52,7 +52,7 @@
 
 #nullable enable
 
-#if !MONOMAC
+#if !MONOMAC && !XAMCORE_5_0
 namespace System.Net.Http {
 #else
 namespace Foundation {