Fix a warning and Unity build (#3663)

Realm/Realm/Logging/Logger.cs

@@ -18,6 +18,7 @@
 
 using System;
 using System.Collections.Concurrent;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.InteropServices;
 using System.Text;
 using System.Threading;
@@ -49,6 +50,7 @@ protected override void LogImpl(LogLevel level, LogCategory category, string mes
     /// A few built-in implementations are provided by <see cref="Console"/>, <see cref="Null"/>, and <see cref="Function(Action{string})"/>,
     /// but you can implement your own.
     /// </summary>
+    [SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "SA1402:File may only contain a single type", Justification = "Original logger is deprecated")]
     public abstract class RealmLogger
     {
         private readonly Lazy<GCHandle> _gcHandle;

Tests/Realm.Tests/Sync/DataTypeSynchronizationTests.cs

@@ -902,14 +902,15 @@ public void NestedCollections_Merge()
                 var list2 = obj1.RealmValueProperty.AsDictionary()["list"].AsList();
                 var dictionary2 = obj1.RealmValueProperty.AsDictionary()["dictionary"].AsDictionary();
 
-                Assert.That(list1, Does.Not.Contain((RealmValue)1));
+                Assert.That(list1, Does.Not.Contains((RealmValue)1));
                 Assert.That(list1, Contains.Item((RealmValue)2));
                 Assert.That(list1, Contains.Item((RealmValue)3));
                 Assert.That(list1, Contains.Item((RealmValue)4));
                 Assert.That(list1, Contains.Item((RealmValue)5));
                 Assert.That(list1, Is.EqualTo(list2).Using(_rvComparer));
 
-                Assert.That(dictionary1, Does.Not.ContainKey("key1"));
+                // Unity Nunit doesn't support Does.Not.ContainKey, so use a more simplistic expression here
+                Assert.That(dictionary1.ContainsKey("key1"), Is.False);
                 Assert.That(dictionary1, Contains.Key("key2"));
                 Assert.That(dictionary1, Contains.Key("key3"));
                 Assert.That(dictionary1, Is.EqualTo(dictionary2).Using(_rvComparer));

Tests/Realm.Tests/Sync/SynchronizedInstanceTests.cs

@@ -803,7 +803,7 @@ public void SyncLogger_WhenLevelChanges_LogsAtNewLevel()
             }
 
             var regex = new Regex("Connection\\[\\d+] Session\\[\\d+]");
-            var logger = RealmLogger.Function((level, msg) =>
+            var logger = RealmLogger.Function((level, _, msg) =>
             {
                 if (regex.IsMatch(msg))
                 {