private void _add(String fieldName, IonValueLite child)
    {
        hasNullFieldName |= fieldName == null;
        int size = get_child_count();

        // add this to the Container child collection
        add(size, child);

        // if we have a hash map we need to update it now
        if (_field_map != null) {
            add_field(fieldName, child._elementid());
        }
    }
private void _add ( String fieldName , IonValueLite child ) { hasNullFieldName |= fieldName == null ; int size = get_child_count ( ) ; add ( size , child ) ; if ( _field_map != null ) { add_field ( fieldName , child . _elementid ( ) ) ; } }
Validates the child and checks locks.

@param fieldName may be null
@param child must be validated and have field name or id set