How many HTTP transactions through a connection in Haproxy

I want to know how many http transactions occur through a specific connection of Haproxy with a client (frontend).

If I could associate connection (session) id with the frontend's request I would be able to count number of log lines with this id, calculating the rate.

Is it possible to do with Haproxy 1.6?

EDIT

The docs state:

At the moment, logs will not indicate whether requests came from the same session or not. The accept date reported in the logs corresponds to the end of the previous request, and the request time corresponds to the time spent waiting for a new request. The keep-alive request time is still bound to the timeout defined by "timeout http-keep-alive" or "timeout http-request" if not set.

Is it possible to retrieve required data with Lua scripting?