I am currently writing my proposal for GSoC 2019 for the TOAST'ing in slices idea. I already have a sketch of the description and approach outline, which I am sending in this e-mail. I would be happy to receive some feedback on it. I've been reading the PostgreSQL source code and documentation in order to understand better how to implement this idea and to write a detailed proposal. I would also be glad to receive some recommendation of documentation or material on TOAST'ing internals as well as some hint on where to look further in the source code.