mysql connector 连接报错，  客户端在 MySqlClient.MySqlDataReader.NextResult() 处报错 ,IIS 进程池 crash 后 db 端提示 Got an error reading communication packets 。

异常时堆栈调用信息：

ServerConnectionInfo.Finallize()

=>ServerConnectionInfo.Dispose()

=>MySqlConnection.Dispose()

=>MySqlConnection.Close()

=>MySqlDataReader.Close()

=》MySqlDataReader.NextResult()

     从堆栈调用信息来看，是从程序中发起了Dispose()，后再调用了MySqlConnection.Dispose()进行关闭。         在这里MySqlConnection.Close()又调用MySqlDataReader.Close()=》MySqlDataReader.NextResult()，从应用代码了解到MySqlConnection.Close()一般应为正常关闭的最后一步，而MySqlDataReader.Close()应在MySqlConnection.Close()之厚，这看起来是个非正常行为。

     报错信息与connector 的 Bug#91106 NullReferenceException in Finalize crashes applications及Bug#90845 

NullReferenceException on connection close比较匹配，易工已通过修改connetor源码进行测试。

Bug#90845：

Description:

A NullReferenceException is thrown on MySqlConnection Dispose

The NullReference came from the setter of the property Reader.

In the getter the driver has a null check but in the setter it is treated as a NotNull value

Bug#91106

Suggested fix:

       The MySqlDataReader that is used underneath by the command and dataadapter should have been disposed of when the commmand and dataadapter were disposed. I think that is probably a bug.

       If it wasn't disposed of correctly then, the finalize method should not assume the driver and driver.stream are not null. or you can catch these exceptions in dispose and not crash the program.