Draft: introduce an changeset discovery sampling based on chain coverage
This new way of sampling is the result of research from Laurent Bulteau, Pierre-Yves David and Florian Horn. This first implementation is basic and will be improved further in this series of changesets.
Building and maintening the chain coverage is currently CPU expensive enough that the method is not competitive time-wise with the exponential sampling used so far. However having the implementation is useful to compare the performance in terms of communication (query and roundtrips) and access if a more time efficient implementation would be useful.
Edited by Florian Horn