rn iOS模拟器无法连接问题 __nw_connection

https://github.com/facebook/react-native/issues/10027

解决方案，亲测可用：

OS_ACTIVITY_MODE

@HADB proposed:

Open Xcode.

Open Product menu.

Select Edit Scheme...

Add the following under Environment Variables:

Name: OS_ACTIVITY_MODE

Value: disable

Run your app again