I'm going through the documentation and I can't find a way how to send a custom-made JSON message wile consuming the RCC api.

In short, the RCC api doesn't tell us how long a call has been going, and so when a new instance of an app is being opened this instance can't know how long busy calls have been up already.

For that I want to use a custom-made signal to request this and then a custom-made signal/reply that follows to give the start time so the new instance can calculate the uptime.

Thanks,

Hannes