public String getCorrelationData() {
        return this.correlationData;
    }
<p>
The base64-encoded binary data used by the sender of the request message to identify which request the response
message is for when it's received.
</p>
<p>
For more information, see <a href="https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901115">
Correlation Data</a> from the MQTT Version 5.0 specification.
</p>
<note>
<p>
This binary data must be based64-encoded.
</p>
</note>
<p>
Supports <a
href="https://docs.aws.amazon.com/iot/latest/developerguide/iot-substitution-templates.html">substitution
templates</a>.
</p>

@return The base64-encoded binary data used by the sender of the request message to identify which request the
        response message is for when it's received.</p>
        <p>
        For more information, see <a
        href="https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901115"> Correlation Data</a>
        from the MQTT Version 5.0 specification.
        </p>
        <note>
        <p>
        This binary data must be based64-encoded.
        </p>
        </note>
        <p>
        Supports <a href="https://docs.aws.amazon.com/iot/latest/developerguide/iot-substitution-templates.html">
        substitution templates</a>.
aws-java-sdk-iot/src/main/java/com/amazonaws/services/iot/model/MqttHeaders.java