Automatically email the evidence.pdf once signing completes

I know how to retrieve the evidence pdf with the below code:

    byte[] evidenceContent = eslClient.downloadEvidenceSummary(packageId);
    Files.saveTo(evidenceContent, "evidence.pdf");

But don't know how to let OSS to automatically email the singers the evidence.pdf once the signing is completed. My below code just attached the complete document pdf to the email, the evidence pdf was not attached. Thanks for your help!

    apiClient = new EslClient(ApiTokenConfig.newBuilder()
            .clientAppId(username)
            .clientAppSecret(password)
            .baseUrl(baseUrl)
            .tokenType(TokenType.OWNER).build(),
            baseUrl + "/api", false, null, false, new HashMap<String, String>());
    apiClient.getAccountConfigService()
            .getAccountFeatureSettings()
            .setEmailDocumentsAndEvidenceSummary(true);
            
    ...
    
    documentPackage.addSigner(SignerBuilder
            .newSignerWithEmail(emailAddress)
            .deliverSignedDocumentsByEmail()
            .withFirstName(fname)
            .withLastName(lname)
            .signingOrder(signingOrder)
            .build());