public void clearAnnotations(SpanNode node) {
        Iterator<Annotation> annIt = iterator(node);
        while (annIt.hasNext()) {
            annIt.next();
            annIt.remove();
        }
    }
Clears all Annotations for a given SpanNode.

@param node the SpanNode to clear all Annotations for.
document/src/main/java/com/yahoo/document/annotation/SpanTree.java