Kindly ask how to support certificate pinning for iOS SDK

[lipengxuan]

Is your feature request related to a problem? Please describe.
For some reason I am currently using V2.0 sdk, I am wondering is there a way I can add certificate pinning logic in iOS SDK or to use it in any version? more specifically, I have a local pem certificate, wants to pin the server side certificate, don't know how to do that

Describe the solution you'd like
an interface function to let me pin certificate

Describe alternatives you've considered
Or a parameter required to check pinning

Additional context
Add any other context or screenshots about the feature request here.