Push of stacked branch create 3+ ssh connections

[Alexander Belchenko]

Initial push of stacked branch create 4 ssh connections:

C:\work\Bazaar\qbzr-stack\0.9.5>bzr push lp:~qbzr-dev/qbzr/0.9.5-stacked
Connected (version 2.0, client Twisted)
Authentication (publickey) successful!
Secsh channel 1 opened.
Using default stacking branch /~qbzr-dev/qbzr/trunk at
bzr+ssh://bialix@bazaar.launchpad.net/%7Eqbzr-dev/qbzr/
Connected (version 2.0, client Twisted)
Authentication (publickey) successful!
Secsh channel 1 opened.
Connected (version 2.0, client Twisted)
Authentication (publickey) successful!
Secsh channel 1 opened.
Connected (version 2.0, client Twisted)
Authentication (publickey) successful!
Secsh channel 1 opened.
Created new stacked branch referring to /~qbzr-dev/qbzr/trunk.

But then second time no-op push create 3 ssh connections:

C:\work\Bazaar\qbzr-stack\0.9.5>timeit bzr push
Using saved push location: bzr+ssh://bialix@bazaar.launchpad.net/~qbzr-dev/qbzr/0.9.5-stacked/
Connected (version 2.0, client Twisted)
Authentication (publickey) successful!
Secsh channel 1 opened.
Connected (version 2.0, client Twisted)
Authentication (publickey) successful!
Secsh channel 1 opened.
Connected (version 2.0, client Twisted)
Authentication (publickey) successful!
Secsh channel 1 opened.
No new revisions to push.

time: 27.375

Establishing every ssh connection require time, so latter behavior is not optimal. I understand
creating 2 connections: 1st for the branch and 2nd for stacked on branch. So what is 3rd?

Pushing non-stacked branch is much faster:

C:\work\Bazaar\qbzr-repo\trunk>timeit bzr push
Using saved push location: bzr+ssh://bialix@bazaar.launchpad.net/~qbzr-dev/qbzr/trunk/
Connected (version 2.0, client Twisted)
Authentication (publickey) successful!
Secsh channel 1 opened.
No new revisions to push.

time: 15.281