protected MessageHandler buildSAMLOutboundProtocolMessageSigningHandler()
        throws ComponentInitializationException {
        MessageHandler messageSigner = new SAMLOutboundProtocolMessageSigningHandler();
        messageSigner.initialize();
        return messageSigner;
    }
<p>buildSAMLOutboundProtocolMessageSigningHandler.</p>

@return a {@link MessageHandler} object
@throws ComponentInitializationException if any.
pac4j-saml/src/main/java/org/pac4j/saml/sso/artifact/DefaultSOAPPipelineFactory.java