optimize if

Author: KirillKurdyukov

src/Ydb.Sdk/src/Ado/Session/PoolingSessionSource.cs

@@ -48,9 +48,6 @@ YdbConnectionStringBuilder settings
 
     public ValueTask<ISession> OpenSession(CancellationToken cancellationToken = default)
     {
-        if (IsDisposed)
-            throw new YdbException("The session source has been shut down.");
-
         cancellationToken.ThrowIfCancellationRequested();
 
         return TryGetIdleSession(out var session)

src/Ydb.Sdk/test/Ydb.Sdk.Ado.Tests/YdbConnectionTests.cs

@@ -412,7 +412,7 @@ public async Task BulkUpsertImporter_MultipleImporters_Parallel()
         var table1 = $"BulkImporter_{Guid.NewGuid():N}_1";
         var table2 = $"BulkImporter_{Guid.NewGuid():N}_2";
 
-        await using var conn = await CreateOpenConnectionAsync();
+        var conn = await CreateOpenConnectionAsync();
         try
         {
             foreach (var table in new[] { table1, table2 })
@@ -467,6 +467,8 @@ await Task.WhenAll(
                 dropCmd.CommandText = $"DROP TABLE {table}";
                 await dropCmd.ExecuteNonQueryAsync();
             }
+
+            await conn.DisposeAsync();
         }
     }