Wrap DbTransaction too

PluralKit.Core/Database/Wrappers/PKTransaction.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Data;
+using System.Data.Common;
+using System.Threading;
+using System.Threading.Tasks;
+
+using Npgsql;
+
+namespace PluralKit.Core
+{
+    public class PKTransaction: DbTransaction, IPKTransaction
+    {
+        public NpgsqlTransaction Inner { get; }
+        
+        public PKTransaction(NpgsqlTransaction inner)
+        {
+            Inner = inner;
+        }
+
+        public override void Commit() => throw SyncError(nameof(Commit));
+        public override Task CommitAsync(CancellationToken ct = default) => Inner.CommitAsync(ct);
+
+        public override void Rollback() => throw SyncError(nameof(Rollback));
+        public override Task RollbackAsync(CancellationToken ct = default) => Inner.RollbackAsync(ct);
+
+        protected override DbConnection DbConnection => Inner.Connection;
+        public override IsolationLevel IsolationLevel => Inner.IsolationLevel;
+        
+        private static Exception SyncError(string caller) => throw new Exception($"Executed synchronous IDbTransaction function {caller}!");
+    }
+}