Need clarifications on subscription

[vporton]

We need some clarifications on subscriptions:

• If subscribe method is called several times with the same parameters, will it lead to duplicate messages from the server?
• What happens if subscribe is called twice, for example, with different accounts parameter? will the two sets of accounts be unioned or will the second subscribe request cancel the first one? what if two sets of accounts are not the same but have non-empty intersection?
• Is there any way to know which message from the server is caused by which subscribe method invocation?