After the modbus device connects to the mapper, the container of the mapper fails.

[NicoleLeeuu]

The Modbus Mapper is running normally. After the device is delivered, the container of the mapper fails.

View the mapper log. The command output is "panic: runtime error: invalid memory address or nil pointer dereference".

Locate the problem. It was found that the payload in the Run() function, located in the mappers/modbus-dmi/device/twindata.go file, did not add the "Expected" data section. This results in an error when accessing msg.Twin.Expected when executing the parse.ConvMsgTwinToGrpc(msg.Twin) function.
Is this a bug in the process of design and implementation? If so, please leave bugfix matters to me.

[QiQi-OvO]

Yes, this is a bug that has been fixed by two PRs(#99, #105), but they haven't been merged into the code repository yet.

[cl2017]

Yes, this is a bug that has been fixed by two PRs(#99, #105), but they haven't been merged into the code repository yet.

Let's review these PRs again and merged it into master