Context

Move the generic part of the error-monad into Lwtreslib (which is then included or some such in the error-monad). The main idea is to focus the error-monad library on error registration, encoding, pp, etc.
Provide more consistent return across all monads (as well as pre-allocated return_*).
Better documentation of Lwtreslib's Monad.

Manually testing the MR

Document the interface of any function added or modified (see the coding guidelines)
Document any change to the user interface, including configuration parameters (see node configuration)
Provide automatic testing (see the testing guide).
For new features and bug fixes, add an item in the appropriate changelog (docs/protocols/alpha.rst for the protocol and the environment, the Development Version section of CHANGES.md for everything else).
Select suitable reviewers using the Reviewers field below.
Select as Assignee the next person who should take action on that MR

Edited Sep 07, 2021 by Raphaël Proust