public FieldValue getRecursiveValue(FieldPath path) {
        RecursiveIteratorHandler handler = new RecursiveIteratorHandler();
        iterateNested(path, 0, handler);
        return handler.retVal;
    }
Using the given field path, digs through the document and returns the matching field value.
If the field path resolves to multiple values, returns an ArrayFieldValue containing the
values.
document/src/main/java/com/yahoo/document/datatypes/FieldValue.java