WebSocket + Protobuf?

# Background:
1. For each following API request (on average):
a. **api/WatchHistories** has 1563 Bytes (Header) + 37 Bytes (Body);
b. **api/Logs** has 1563 Bytes (Header) + 15 Bytes (Body)
2. 854/1563 bytes HTTP headers is "Authorization" field.
3. "WatchHistories" report occurs once per second.
4. "Event" report occurs frequently when "watching".

# Why WebSocket?
Duplex Communication!
1. Real-time update: Someone else changed the transcription? We want real time update.
2. Analytics: We want to know when user get disconnected.
3. Shorter packet: After connection established, we don't need to send Authorization header
4. "CT Party": learn with your friends

# Why Protobuf?
1. Shorter packet
2. High performance

# Cons
1. Pool of active users
2. TCP timeout