Using Android API23 Call and Call.Details Class to get Disconnect Cause for Calls

Question

All i am trying to do is to get the reason why a call was disconnected. I have searched but i am unable to find any solution for API level under 23. but in API 23 we have;

1. https://developer.android.com/reference/android/telecom/Call.html
2. https://developer.android.com/reference/android/telecom/Call.Details.html

Call.Details.getDisconnectCause() returns the Disconnect Cause object but i am unable to understand how i can use use the CALL class or DETAILS class or which broadcasts to use to get these objects(if any).

So is there a broadcast i have to handle that returns call states in extras? or is there another way to use this class?