when editing buffer contents and using :w instead of HelperSave, use Vim events to run an autocommand that prompts for HelperSave, not :w.
test if you can save with :w, because the buffer should be readonly, so only HelperSave should work.
Indeed, when user does :w, an error message appears:
E382: cannot write, 'buftype' option is set
I should adjust error message to also write: use HelperSave to save data added.
Or make :w to call HelperSave ... well, user might be confused
when editing buffer contents and using :w instead of HelperSave, use Vim events to run an autocommand that prompts for HelperSave, not :w. test if you can save with :w, because the buffer should be readonly, so only HelperSave should work. Indeed, when user does :w, an error message appears: E382: cannot write, 'buftype' option is set
I should adjust error message to also write: use HelperSave to save data added.
Or make :w to call HelperSave ... well, user might be confused