Check the number of records generated by jr

[ram-pi]

i.e.

jr template run -n 500 -f 10ms -d 1m --embedded '{{city}};{{format_float "%.1f" (floating 40 5)}}' --seed 1 1>/dev/null

If jr can't send all the messages (total=duration/frequency*n), it should tell the user how many messages are left.

Proposed output:

Elapsed time: 1m0s
Data Generated (Objects): 2981500
Unsent records (Objects): 18500
Data Generated (bytes): 40671735
Throughput (bytes per second):    676196