With an average runtime of 18.7674, this implies 1876ns
per trace, which is far in excess of the 370ns claimed in
doc/developers-guide/tracing-cln-performance.md.
We also add a tag in there, so we measure that!
Results on my laptop:
real 0m18.524000-19.100000(18.7674+/-0.21)s
user 0m16.171000-16.833000(16.424+/-0.26)s
sys 0m2.259000-2.400000(2.337+/-0.059)s
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>