add a troubleshooting mode

What if Nighthawk had a mode where it tried to send only a handful of requests to the target and dumped the full output?

This would also be an opportunity to dump the full request:
- what protocol was used
- what IP was used
- headers sent (e.g. tracing GUID, from command line, from custom `RequestSource`)

If you couldn't connect to the target, there are multiple possibilities that could be cleared up by a detailed printout. If you are getting 4xx or 5xx errors, sometimes it's interesting to look at the response headers.

Also, in some environments, a Nighthawk service is actually the only tool that has connectivity to the system under test, so this could also be used as a heavy duty ping tool while troubleshooting a testbench. To accomplish this, I have sometimes resorted to running 10 qps for 5 seconds, but the only feedback I have to work with is counters.