private void refresh(final boolean fetch) {
        if (fetch) {
            // Fetch data from the server to update the tree.
            fetchData();
        } else {
            // Just quickly update the display using previously cached data.
            update();
        }
    }
For use when setting an initial value for the filter.
stroom-core-client/src/main/java/stroom/explorer/client/presenter/ExplorerTreeModel.java