Agent TCP4 not responding to RMW stream or packet

Issue template

• Hardware description:
  Agent running on Ubuntu 22.04 x86)64
  Firmware on Raspberry PI Pico W
• RTOS: FreeRTOS
• Installation type: micro_ros_setup
• Version or commit hash: Humble

Steps to reproduce the issue

Agent running in TCP4 mode:
$ ros2 run micro_ros_agent micro_ros_agent tcp4 -p 8000

Firmware is using LWIP Sockets under Freertos as a custom transport rmw (rmw_uros_set_custom_transport). Tested both stream and packet communication modes.

Expected behavior

Would expect some acknowledge package or activity from the Agent.

Actual behavior

Agent is listening on port 8000. It accepts the connection. Data is sent from the firmware to the Agent but no response from the agent.

Additional information

I've not managed to find any blogs or code examples using tcp4 comms on the Agent. Can I confirm that this does talk rmw and whether this should be stream or packet mode?

Start with the micro_ros_agent tcp4 -p 8000 command and the firmware's rmw_uros_set_custom_transport configuration using LWIP sockets on FreeRTOS. Compare stream and packet communication and verify whether the Agent responds to the firmware data; document the required mode or reproduce a confirmed fix.