Fix dispose ordering bug (#93) (#95)

Author: osudude

.gitignore

@@ -182,3 +182,4 @@ UpgradeLog*.htm
 # Microsoft Fakes
 FakesAssemblies/
 /.vs/serilog-sinks-mssqlserver/v15/sqlite3
+/.vs/serilog-sinks-mssqlserver/v15/Server/sqlite3

src/Serilog.Sinks.MSSqlServer/Sinks/MSSqlServer/MSSqlServerSink.cs

@@ -45,7 +45,7 @@ public class MSSqlServerSink : PeriodicBatchingSink
 
         readonly string _connectionString;
 
-        readonly DataTable _eventsTable;
+        private DataTable _eventsTable;
         readonly IFormatProvider _formatProvider;
         readonly string _tableName;
         readonly string _schemaName;
@@ -411,10 +411,13 @@ private static bool TryChangeType(object obj, Type type, out object conversion)
         /// <param name="disposing"></param>
         protected override void Dispose(bool disposing)
         {
+            base.Dispose(disposing);
+
             if (_eventsTable != null)
+            { 
                 _eventsTable.Dispose();
-
-            base.Dispose(disposing);
+                _eventsTable = null;
+            }
         }
     }
 }