hg debugwireproto is useful for testing HTTP interactions. Possibly
more useful than get-with-headers.py. But one thing that makes it
annoying for mid-level tests is that it logs all API calls, such
as readline(). This makes output - especially headers - overly
verbose.
This commit teaches our file and socket observers to not log API
calls on functions dealing with data.
We change the behavior of hg debugwireproto to enable this mode
by default. --debug can be added to restore the previous behavior.
As the test changes demonstrate, this makes tests much easier to
read. As a bonus, it also removes some required (glob) over lengths
in system call results.
One thing that's lacking is knowing which side sent data. But we can
fix this in a follow-up once it becomes a problem.