# System.Data.Common

``` diff
 namespace System.Data.Common {
     public abstract class DbConnection : Component, IDbConnection, IDisposable {
+        public virtual Task CloseAsync();
-        public virtual Task CloseAsync(CancellationToken cancellationToken = default(CancellationToken));

     }
     public abstract class DbDataReader : MarshalByRefObject, IDataReader, IDataRecord, IDisposable, IEnumerable {
+        public virtual Task CloseAsync();
-        public virtual Task CloseAsync(CancellationToken cancellationToken = default(CancellationToken));

     }
 }
```

