Switch MsQuicOpen to MsQuicOpenVersion (#54443)

* Switch MsQuicOpen to MsQuicOpenVersion

MsQuicOpenVersion is designed so we can update the API without breaking old consumers. The version of MsQuic specified in the readme already has this change, so it is safe to completely switch over.

Also switches the API to function pointers, as it was easier then updating the delegate too.

* Add version contant

src/libraries/System.Net.Quic/src/System/Net/Quic/Implementations/MsQuic/Internal/MsQuicApi.cs

@@ -119,18 +119,19 @@ private MsQuicApi(NativeApi* vtable)
 
         internal static bool IsQuicSupported { get; }
 
+        private const int MsQuicVersion = 1;
+
         static MsQuicApi()
         {
-            // TODO: Consider updating all of these delegates to instead use function pointers.
             if (NativeLibrary.TryLoad(Interop.Libraries.MsQuic, typeof(MsQuicApi).Assembly, DllImportSearchPath.AssemblyDirectory, out IntPtr msQuicHandle))
             {
                 try
                 {
-                    if (NativeLibrary.TryGetExport(msQuicHandle, "MsQuicOpen", out IntPtr msQuicOpenAddress))
+                    if (NativeLibrary.TryGetExport(msQuicHandle, "MsQuicOpenVersion", out IntPtr msQuicOpenVersionAddress))
                     {
-                        MsQuicOpenDelegate msQuicOpen =
-                            Marshal.GetDelegateForFunctionPointer<MsQuicOpenDelegate>(msQuicOpenAddress);
-                        uint status = msQuicOpen(out NativeApi* vtable);
+                        delegate* unmanaged[Cdecl]<uint, out NativeApi*, uint> msQuicOpenVersion =
+                            (delegate* unmanaged[Cdecl]<uint, out NativeApi*, uint>)msQuicOpenVersionAddress;
+                        uint status = msQuicOpenVersion(MsQuicVersion, out NativeApi* vtable);
                         if (MsQuicStatusHelper.SuccessfulStatusCode(status))
                         {
                             IsQuicSupported = true;
@@ -148,6 +149,7 @@ static MsQuicApi()
             }
         }
 
+        // TODO: Consider updating all of these delegates to instead use function pointers.
         internal RegistrationOpenDelegate RegistrationOpenDelegate { get; }
         internal RegistrationCloseDelegate RegistrationCloseDelegate { get; }
 

src/libraries/System.Net.Quic/src/System/Net/Quic/Implementations/MsQuic/Interop/MsQuicNativeMethods.cs

@@ -51,10 +51,6 @@ internal struct NativeApi
             internal IntPtr DatagramSend;
         }
 
-        [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
-        internal delegate uint MsQuicOpenDelegate(
-            out NativeApi* registration);
-
         [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
         internal delegate uint SetContextDelegate(
             SafeHandle handle,