void rebuild() {
        final long now = System.currentTimeMillis();
        final long newTimeMs = minExplorerTreeModelBuildTime.getAndUpdate(prev -> Math.max(prev, now));
        final long newId = currentId.incrementAndGet();
        LOGGER.trace(() -> LogUtil.message("rebuild called, newTime: {}, newId: {}",
                Instant.ofEpochMilli(newTimeMs), newId));
        explorerSession.setMinExplorerTreeModelId(newId);
    }
Set state such that the next call to getModel will trigger an update
stroom-explorer/stroom-explorer-impl/src/main/java/stroom/explorer/impl/ExplorerTreeModel.java