If this directive is set to 1 (on), the server checks whether the minimum number of threads are available at a listen socket, after accepting a connection but before sending a response to the request. Use this directive, when the server handles request that take a long time, such as those that perform long database connections. By default, this directive is set to 0 (off) and as a result, the server checks whether the minimum number of threads are available at a listen socket, only after sending a response to the request.
0 (off)