flowchart

Universe = Vec<Symbol>
1. Get Universe from config (public stream)
2. Get Trading symbols (need private + public stream)
3. Book will be modified by ApiManager
4. Book will be viewed by Strategy/AlphaProvider

ApiManager: 
1. Determine what websocket listeners to init according to Universe
2. For different websocket stream:
	1. Public data
		- Maintain the newest orderbook in Universe-Symbol-book
		- Feed add/delete/trade to CC, and let CC send to alpha provider/Strategy.
	2. Private data
		- Send standadized update messages to order manager.

Order manager:
1. Send requests to CC, CC -> api manager, api manager sends responses to order manager
2. api manager: private data to CC, CC -> order manager
3. Orders: aggressive or passive

Alpha provider:
1. Listen to add/delete/trade from CC
2. Calculate the alphas
3. Provide alpha to Strategy

Strategy:
1. Has read access to order manager/alpha provider/Universe, know the status of every orders
2. Only react to packet-end
3. Decide when to send/cancel/modify orders, and PostOnly/IoC order type, order size and price.
4. For different order state, decide how to handle them.

CC:
ALL

init order:


TODO:
WebsocketClient: hang central_controler to callback

SOP:
When finished developing a new exchange public data, please add to src/apis/apimanager.rs
1. WebsocketClient::EXCHANGE(EXCHANGE_CLIENT)
2. source name to new client
3. start event loop to websocket_message_consumer (can't implement a trait for these shits.)