Instead of packing the note for public user before passing it to
streams, the note is now either packed for the user the respective
stream belongs to (`mainStream`) or not packed at all and then packed
later (`notesStream`).
Because this is a new common task between different channels, a shared
implementation of packing a note from notesStream is created. This
implementation will simply skip a note if it is not visible to the user
that the channel belongs to.
Johann150
cfa371b52b
