1. A method of operating a content delivery node that caches content for delivery to end user devices, the method comprising: during execution of an application thread responsive to content request activity of at least an end user device, identifying a secure layer connection request within the application thread; responsive to the secure layer connection request, initiating a security handshake process as a handshake thread selected from among a pool of idle handshake threads to execute the security handshake process for the application thread; and in response to the handshake thread completing the security handshake process, returning to the application thread and returning the handshake thread to the pool of idle handshake threads.