if (this.delegate != null) {
            return this.delegate.getTreeInternal();
        }
        return null;
    }

    /**
     * @param t
     */
    private synchronized void switchTree(final SmbTreeImpl t) {
        try (SmbTreeImpl old = getTree()) {
            if (old == t) {
                return;
            }
            final boolean wasAcquired = this.treeAcquired;