code: public final String asString(final Format format, final StructuredDataId structuredDataId) {
          final StringBuilder sb = new StringBuilder();
          asString(format, structuredDataId, sb);
          return sb.toString();
      }
docs: Formats the structured data as described in RFC 5424.
  
  @param format           "full" will include the type and message. null will return only the STRUCTURED-DATA as
  described in RFC 5424
  @param structuredDataId The SD-ID as described in RFC 5424. If null the value in the StructuredData
  will be used.
  @return The formatted String.