Imagine you're designing a web application that requires real-time communication between the client and server. Which protocol(s) would be suitable for implementing this feature, and how would you ensure efficient data transfer?

WebSocket is suitable for real-time communication between the client and server because it establishes a persistent connection that allows bidirectional data flow with low latency. This eliminates the overhead of establishing new connections for each exchange, making it efficient for real-time applications such as chat, gaming, or collaborative editing. HTTP Long Polling involves repeated client-server requests, leading to higher latency and increased server load, making it less efficient for real-time scenarios. MQTT and XMPP are messaging protocols often used for IoT and instant messaging, respectively, but they are not optimized for real-time web applications like WebSocket.