updating a snapshot during/after a run

I can understand that you don't support modifying the data in the databases. Is the same true about updating values of dummy parameters that store information about instrument which cannot be connected to qcodes. Very often, we forget to update then before (long) measurements and it would be handy to be able to make the update during / after the measurement. It could have a form of a note... Any solution which would avoid creating an additional file would be fantastic.

The issue does not name a file, test, or entry point. Start by locating the snapshot and measurement lifecycle handling, then determine whether dummy instrument parameters can be updated during or after a run without creating another file; done means a documented, usable solution for preserving those updates.

Written by the indexing model from the issue text.