         # If something changed, then change in our local store, and also kick off a save to the backend.
         if not immutable.is(new_val, cur)
             @_value_local = @_value_local.set(id, new_val)
+            @_last_set = new Date() - 0
             @save(cb)
             @emit('change', [id])  # CRITICAL: other code assumes the key is *NOT* sent with this change event!
         return new_val

            cb?()
            return

        at_start = @_value_local
        changed = @_changes()

        # Send our changes to the server.

        #    if Math.random() <= .5
        #        query = []
        #@_fix_if_no_update_soon() # -disabled -- instead use "checking changefeed ids".
        last_set = @_last_set  # when set was last called
        @_client.query
            query   : query
            options : [{set:true}]  # force it to be a set query
