public Map<String, String> data() {
        return data;
    }
Returns the transformed data, with variables replaced with corresponding values from the
ConfigProvider instances if found.

<p>Modifying the transformed data that is returned does not affect the {@link ConfigProvider} nor the
original data that was used as the source of the transformation.

@return data a Map of key-value pairs
clients/src/main/java/org/apache/kafka/common/config/ConfigTransformerResult.java