use thenAnswer in test

Change static method to instance menthod

Change static method to instance menthod

Change static method to instance menthod

fix readme typo

Test response data format.

through exception if permission is not granted

nullify pendingResult after it's called

format code

check multiple requests

Add test

polish

Update reademe fiel

Catch exception and return the error back to dart for fetching phone logs

Polish.