SERVER-103733 will move the execution of async response callback processing in mongos from the network thread to the "baton" subsystem.
To complete the work on SERVER-103733, the following TODO comment in task_executor.cpp needs to get addressed:

    // TODO SERVER-103733 Consider if we can fix the pool size to 1 once getMores from router
    // to shards happen on the baton.

I would prefer to keep the configurability for now, in case there is a demand for it in certain workloads. So I will not remove the configurability as part of SERVER-103733.

However, removing the configurability and fixing the pool size to 1 may still be our longer term goal, as hinted here.

Creating this ticket to preserve the original request of considering if the task executor pool size can be fixed to 1, and assigning to SP as code owners of the task executor pool.