Poor performance of MDSAL Northbound mapped on a Netconf connector

When RestPerfClient is run on MDSAL Northbound directly, the MDSAL Northbound manages to serve over 400 requests per second. However when it is run on MDSAL Northbound mapped on a Netconf Connector, the request rate drops significantly. The RestPerfClient output log attached to NETCONF-169 suggests it is below 220 per second but the exact rate could not be determined because of NETCONF-169 combined with lack of support for configuring the timeouts in RestPerfClient (which is a new feature) in the performance test suite.

Yes, I expect a performance drop when going through a Netconf connector versus going directly but a performance drop of over 50% is way too severe.

Looking into the logs reveals massive amount of "Timing out for 1 session(s) with id <24-to-26-random-chars>" warnings emitted during the time when RestPerfClient emitting the requests to the Netconf connector mapped MDSAL Northbound.