问题
How can I check the native call is running before call start or accept.
Whatsapp is not allowing to call when the user hit the call icon through it's application while native call in progress. It's showing alert view "you can't place a call on Whatsapp if you are already on a phone call iOS SDk Call kit"
Example : Device A and Device B on native call in progress. Now Device B open the app and wants to call to device C through Application. I am not able to find the native in progress call in CXProvider class.
Is there any way I can check native line call before make or accept call.
来源：https://stackoverflow.com/questions/49257417/where-can-i-track-native-call-when-user-wants-to-call-through-app-on-another-dev