NetworkExtension NWPath private extension to obtain interface name

NENWPath+Private.swift

import NetworkExtension

extension NetworkExtension.NWPath {
    var interfaceName: String? {
        let interface = self.value(forKeyPath: "_internalPath.direct") as? nw_interface_t

        return interface.map { String(cString: nw_interface_get_name($0)) }
    }
}