public String getSubjectFromWIF() {
        return this.subjectFromWIF;
    }
Get the identifier returned from the Identity Provider for the
authenticated user.  This value is returned as part of the
AssumeRoleWithIdentityResult

@see com.amazonaws.services.securitytoken.model.AssumeRoleWithWebIdentityResult

@return The identifier returned from Identity Provider
aws-java-sdk-sts/src/main/java/com/amazonaws/auth/WebIdentityFederationSessionCredentialsProvider.java