Bug: With multiple listeners, call to dispose does not unregister

[QuintinKrugerMC]

Problem/Opportunity

The following description is based on the file listener.js

When there is a single listener of a type (defined by listener_id), the call to unregister happens as expected

After the splice call, the array for this listener is empty

Then the if resolves as expected and the call to unregister happens successfully

However when there are multiple listeners for the listener type, the if condition resolves to false and the call to unregister does not happen as expected

Listener removed out of array leaving the other listeners in place after splice call is made

But then the if condition resolves to false and the call to unregister does not happen as expected

Steps to reproduce

1. Ensure the thunderjs server has a listener to connect to
2. Connect to the listener with mutliple listeners (2 atleast)
3. Perform dispose call of one of the listeners
4. Notice that although listener's dispose function gets executed, the call to unregister in network tab is never seen (on browser)

Expected Behavior

The call to dispose of a listener should always unregister, regardless if the number of listeners in the array of listeners for a given listener_id

Actual Behavior

The listener gets removed from the array of listeners however the network call to truly unregister for the given listener does not get made

Notes (Optional)

No response

[QuintinKruger]

I was under the false illusion that for each registration of a callback to an event, a new websocket is opened and as such I expected that every call to dispose should have a matchin unregsiter API call

However after further digging I came to the conclusion that this is not true - a single websocket is established for multiple callback functions to a single websocket session.

As we call dispose, the corresponding callback function is removed however the websocket is still kept open until ALL callbacks have been removed. Only on the removal of the last callback does an API call get makde to unregister and close the websocket

Apologies for opening the issue without doing this analysis prior