AFConnectionOpen failed to return a valid connection

[ryanluoo]

• Xcode Version 12.0.1 (12A7300)
• iPhone 6S Plus (iOS 14.0.1)
• Test Command : ios-deploy -f -l/DCIM

As you can see, AFConnectionOpen failed to return a valid connection, then the assert will fail

This issue is introduced since #471

[ryanluoo]

@Ukalnins Could you kindly help to look into this issue ?