clonebundles: add support for inline (streaming) clonebundles
The idea behind inline clonebundles is to send them through
the ssh or https connection to the Mercurial server.
We've been using this specifically for streaming clonebundles,
although it works for 'regular' clonebundles as well
(but is less relevant, since pullbundles exist).
We've had this enabled for around 9 months for a part
of our users.
A few benefits are:
- no need to secure an external system,
since everything goes through the same Mercurial server
- easier scaling (in our case: no risk of inconsistencies
between multiple mercurial-server mirrors and nginx clonebundles hosts)
Remaining topics/questions right now:
- The inline clonebundles don't work for https yet.
This is because httppeer doesn't seem to support sending client
capabilities.
I didn't focus on that as my main goal was to get this working
for ssh.
Our full contribution guidelines are in our wiki, please see:
https://www.mercurial-scm.org/wiki/ContributingChanges
If you just want a checklist to follow, you can go straight to
https://www.mercurial-scm.org/wiki/ContributingChanges#Submission_checklist
If you can't run the entire testsuite for some reason (it can be
difficult on Windows), please at least run `contrib/check-code.py` on
any files you've modified and run `python contrib/check-commit` on any
commits you've made (for example, `python contrib/check-commit
273ce12ad8f1` will report some style violations on a very old commit).