End-to-end encryption and privacy controls.
Message and call for free* around the world.
Group conversations made simple.
Say it with stickers, voice, GIFs and more.
Reach your customers from anywhere.
Swift: 다중 옵셔널 (Nested optional; ??)의 존재 이유와 언래핑 방법 http://yoonbumtae.com/?p=5313