@Override
    public void visitMembers(ObjectVisitor visitor) {
        super.visitMembers(visitor);
        visitor.visit("removeIfZero", removeIfZero);
        visitor.visit("createIfNonExistent", createIfNonExistent);
    }
Returns true if this has the property removeIfZero (only relevant for weighted sets)

@return removeIfZero property
document/src/main/java/com/yahoo/document/WeightedSetDataType.java