Hello all,

I created a second draft:

- I improved the naming

- I moved `transactional` to srfi-167 and adapted the specification to make it

  possible to compose layers relying on srfi 167. Unlike previously this layer

  doesn't take ownership of the transaction.

See https://github.com/scheme-requests-for-implementation/srfi-168/pull/1

And wip https://github.com/scheme-requests-for-implementation/srfi-167/pull/2

Also let me know what I can do to improve the specification or in general how

to help people get a good grasp of how it works?

Thanks.