当另一个 read 操作挂起时不能调用 Read 方法。

在 System.Net.Security._SslStream.ProcessRead(Byte[] buffer, Int32 offset, Int32 count, AsyncProtocolRequest asyncRequest)
在 System.Net.Security.SslStream.Read(Byte[] buffer, Int32 offset, Int32 count)
在 MySql.Data.MySqlClient.TimedStream.Read(Byte[] buffer, Int32 offset, Int32 count)
在 MySql.Data.MySqlClient.MySqlStream.ReadFully(Stream stream, Byte[] buffer, Int32 offset, Int32 count)
在 MySql.Data.MySqlClient.MySqlStream.LoadPacket()
在 MySql.Data.MySqlClient.MySqlStream.ReadPacket()
在 MySql.Data.MySqlClient.NativeDriver.GetResult(Int32