How to add Controlnet-specific inputs, when doing API requests for shared A1111 webui

[XieBaoshi]

Any idea how to get Controlnet work correctly with API requests for online Automatic1111?
It seems to have a separated payload that coming before the main part (t2i or i2i), and it can have many possible variants of fn_index.
Still not managed to make controlnet input work along with the t2i task, even though the session hash is the same.

[missionfloyd]

https://github.com/Mikubill/sd-webui-controlnet/wiki/API#integrating-sdapiv12img