Authority rules
Authority rules for the Legacy Market Data API include the following:
Any consumer may send a subscription to get data
Only one publisher can send data and errors for a given source key
To avoid conflicting data, only one publisher should try and transmit data for any given source key.
Only consumers that have sent a subscription can send unsubscribe requests
To ensure that the publisher keeps a correct reference count, only consumers that have an active subscription can send unsubscribe requests.
