this.swift

class Messenger {
    
    func log(_ message: String) {
        print(message)
    }
    
    func logThis() {
        DispatchQueue.main.async { [weak self] in
            guard let this = self else { return }
            this.log("1")
            DispatchQueue.main.async { [weak this] in
                this?.log("2")
            }
        }
    }
    
}