Traditionally, there are two strategies:

1) Use the network thread pool to also run application code. Then your entire program has to be super careful to not block or do CPU intensive work. This is efficient but leads to difficult to maintain programs.

2) The network thread pool passes work back and forth between an application executor. That way, the network thread pool is never starved by the application, since it is essentially two different work queues. This works great, but now every request performs multiple thread hops, which increases latency.

There has been a lot of interest lately to combine scheduling and work stealing algorithms to create a best of both worlds executor.

You could imagine, theoretically, an executor that auto-scales, and maintains different work queues and tries to avoid thread hops when possible. But ensures there are always threads available for the network.