Transaction Identifier not checked in ModbusTcpClient, resulting in incorrect data

[LanderV-Vintecc]

The Transaction Identifier (the field identifying each modbus transaction) is ignored in ModbusTcpClient and ModbusTcpClientAsync:

FluentModbus/src/FluentModbus/Client/ModbusTcpClient.cs

Line 294 in bbd7dcd

_ = reader.ReadUInt16Reverse(); // 00-01 Transaction Identifier

FluentModbus/src/FluentModbus/Client/ModbusTcpClientAsync.cs

Line 98 in bbd7dcd

_ = reader.ReadUInt16Reverse(); // 00-01 Transaction Identifier

According to the official docs, it is necessary to check it though: https://www.modbus.org/docs/Modbus_Messaging_Implementation_Guide_V1_0b.pdf (page 10):

Several MODBUS transactions can be activated simultaneously on the same TCP Connection.
Remark: If this is done then the MODBUS transaction identifier must be used to uniquely identify the matching requests and responses.

A real-life example:

A read request is written with transaction identifier 10.
The following message is a response with transaction identifier 0F.
Then, we get the response with transaction identifier 10.

Ignoring the transaction identifier will result in an incorrect value.

[sshalayev]

Ran into similar issue. If you create several requests before getting the first response, things become totally messed up.
Generally speaking, it just can't work asynchronously by design.