Implement MySqlDataReader.Depth.

Author: bgrainger

src/MySqlConnector/Core/ResultSet.cs

@@ -263,6 +263,8 @@ Row ScanRowAsyncRemainder(PayloadData payload, Row row_)
 			}
 		}
 
+		public int Depth => 0;
+
 		public string GetName(int ordinal)
 		{
 			if (ColumnDefinitions == null)

src/MySqlConnector/MySql.Data.MySqlClient/MySqlDataReader.cs

@@ -205,7 +205,7 @@ public override long GetChars(int ordinal, long dataOffset, char[] buffer, int b
 
 		public override IEnumerator GetEnumerator() => new DbEnumerator(this, closeReader: false);
 
-		public override int Depth => throw new NotSupportedException();
+		public override int Depth => GetResultSet().Depth;
 
 		protected override DbDataReader GetDbDataReader(int ordinal) => throw new NotSupportedException();