List<ColumnKey> keysConsumedOrWhatever = new ArrayList<>();
        for(Map.Entry<ColumnKey, Column> entry : queuedColumns.entrySet()) {
            Column c = entry.getValue();
            if (c != null && canRegen(c.lastChanged)) {
                keysConsumedOrWhatever.add(entry.getKey());
            }
        }

        for (ColumnKey key : keysConsumedOrWhatever) {
            queuedColumns.remove(key);
        }