@Override
    protected void buildAuditMessage(StringBuilder builder) {
      builder
        .append("User(")
        .append(this.userName)
        .append("), RemoteIp(")
        .append(this.remoteIp)
        .append(")");
      if (StringUtils.isNotEmpty(this.proxyUserName)){
        builder
            .append(", ProxyUser(")
            .append(this.proxyUserName)
            .append(")");
      }
    }
Appends to audit event details the user name and remote ip of the host
where user actions originates from.

@param builder builder for the audit message details.
ambari-server/src/main/java/org/apache/ambari/server/audit/event/AbstractUserAuditEvent.java