After running a load test of a VS with custom code that had a configurable delay time for the response, netstat showed several sessions with a CLOSE_WAIT status.
These sessions did not disappear after running the benchmark.
Only stopping and starting the VSE would release the sessions.
Release : 10.7
Component : DevTest Virtual Service
Initializing the delay time property in the beanshell custom code with a value after each iteration, resolved the problem.