TServerSocketThread objects listen for requests on the network and delegate them to client socket threads. Each client socket thread is added to the list ThreadPool after it is created. Creating and destroying client socket threads can be quite time consuming, so whenever one completes its work on a given connection it becomes dormant. When a new connection request is received, the ThreadPool is checked for dormant client socket threads. If one is available, it is assigned the connection. If not, a new client socket thread created. By reusing previously-created threads, the application's performance is improved. 

TClientSocketThread 

ClearThreadPool