@Override
    public DataType setInputType(DataType inputType, TypeContext context) {
        super.setInputType(inputType, DataType.STRING, context);
        return ArrayDataType.getArray(DataType.STRING);
    }
The destination the chunks will be written to on the form [schema name].[field name]
indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/ChunkExpression.java