[Swift 5.6 compat] use compat threading library
[Swift 5.6 compat] use compat threading library

glessard/swift,apple/swift,glessard/swift,roambotics/swift,glessard/swift,glessard/swift,roambotics/swift,roambotics/swift,glessard/swift,apple/swift,apple/swift,apple/swift,roambotics/swift,glessard/swift,apple/swift,roambotics/swift,apple/swift,roambotics/swift