I could build a custom config for the dispatcher like [this](https://groups.google.com/forum/?fromgroups=#!topic/akka-user/OMgT2Nn3_xY), but it looks like it won't be just a Dispatcher, but a whole Actor System. Last time I checked, there wasn't any facilities to configure Dispatchers programmatically.

There could be another way : we could keep track of the time shift caused by this additional processing take it into account in the time response time calculation. That wouldn't fix issues caused by blocking, but response times would be correct at least.