smarter load balancer polling

[olix0r]

Currently, we check all connections each time the load balancer is polled. This is inefficient, especially as the number of active connections increases. As the docs explain, we can be much more efficient about checking only relevant updates.

[tamird]

@olix0r this should have been closed by ea507f7.

FYI this doesn't do what you think:

Fixes #1 #2 #3"

Each issue needs its own "fixes":

Fixes #1 Fixes #2 Fixes #3