etl

809ccafb - Squashed commit of the following:

Squashed commit of the following: commit fa9d9592aa7cb686ae1e8c6eeedfcbfda7a59835 Author: John Wellbelove <github@wellbelove.co.uk> Date: Thu Nov 26 19:26:11 2020 +0000 format_spec may be constexpr