How to add protecting balls to new sharp features discovered while meshing?

[stefango74]

Issue Details

How can I protect sharp features while meshing, for a surface representation where it is not feasible to detect those sharp features beforehand but only while refining?
I tried to add features while meshing but they are only queried initially.
Changing the weights of points of a triangle that was part of a sharp feature while meshing resulted in weird errors.