DropInActivity with specified options.DropInActivity or calling
DropInResult.fetchDropInResult(Activity, String, DropInResultListener).DropInResult.fetchDropInResult(Activity, String, DropInResultListener)Activity.onActivityResult(int, int, android.content.Intent) if
responseCode is not Activity.RESULT_OK or
Activity.RESULT_CANCELED.Intent that can be used in Activity.startActivityForResult(Intent, int)
to launch DropInActivity and the Drop-in UI.DropInResult.fetchDropInResult(Activity, String, DropInResultListener) will be
returned here.DropInRequest.amount(String), Drop-In will request a 3D Secure verification for
any new cards added by the user.