Can, for example, be used to benchmark block connections.
Can be used to monitor in- and outbound node traffic. Based on ealier work by jb55. Co-authored-by: William Casarin <jb55@jb55.com>
Both added files are extended in the following commits. doc/usdt.md is based on earlier work by laanwj. Co-authored-by: W. J. van der Laan <laanwj@protonmail.com>