What Android apps are there that allow you to relay a call (or messages) to another device?

Question

Android

At WWDC 2014 , iOS8 was shown with the "iPhone Cellular Calls" feature: if your iPhone is lying in your bag, and you are reading something on your iPad, you can answer an incoming call from both iPhone and iPad. In this case, the call will not go through FaceTime, but through the operator to which the SIM card is connected in the iPhone. Convenient, isn't it?
So the question arose by itself - is there a similar solution for Android devices? And are there any solutions for relaying messages? (I saw a manual on Habré on creating a relay notification application on Windows)
I would also like to know if solutions already exist based on the existing "iPhone Cellular Calls"? It would be nice to answer calls on Samsung Galaxy via iPad or iPod Touch.
PS I actively use both Apple and Android devices.

Answer 1

There are no such ready-made applications. We have already written half, there are not enough 2 developers and a month of time.

Answer 2

I use SMS Forwarding, if the call is not answered, then it sends an SMS to the other one about the call :)