private void recurseExplorerNodes(final ExplorerNode node, Set<DocRef> docRefs) {
        if (!node.getType().equals(GitRepoDoc.TYPE)) {
            docRefs.add(node.getDocRef());
        }
        List<ExplorerNode> children = this.explorerNodeService.getChildren(node.getDocRef());
        for (ExplorerNode child : children) {
            // Don't recurse any child GitRepoDoc nodes
            if (!child.getType().equals(GitRepoDoc.TYPE)) {
                this.recurseExplorerNodes(child, docRefs);
            }
        }
    }
Finds all the children of a GitRepo node, down to the next GitRepo node.
Runs recursively.

@param node    The root node of the search.
@param docRefs The set of DocRefs that were found.
stroom-gitrepo/stroom-gitrepo-impl/src/main/java/stroom/gitrepo/impl/GitRepoStorageService.java