Provide a hook called before the session save

[chemzqm]

So that the user could define a function to close the buffers which can not be restored by vim-session, this could prevent the empty window(s) shown on vim restart.

[alexozer]

It would also be nice to have a hook on startup too (probably an autocmd) so the user could set up some session-specific vim variables that vim-session discards.

[blueyed]

@alexozer There's SessionLoadPost - see https://github.com/xolox/vim-session/issues/141.