Use const std::chrono::milliseconds type for secondsPerPaket_
instead of defining seconds =
std::chrono::duration<double, std::ratio<1>>. That way we avoid some
useless casts later.

Change type of sent_samples to uint64_t: unsigned is kind of small for
this usage and getNextTimestamps expects seq of type uint64_t.

Simplify code in readFunction() and process().

Change-Id: I6ac7fd1b4553cfe5982a3d05a6467b8085f758a4
Reviewed-by: Philippe Gorley <philippe.gorley@savoirfairelinux.com>