code: public List<String> getQualityCSV(HttpHeader header) {
          QuotedQualityCSV values = null;
          for (HttpField f : this) {
              if (f.getHeader() == header) {
                  if (values == null)
                      values = new QuotedQualityCSV();
                  values.addValue(f.getValue());
              }
          }
  
          return values == null ? Collections.emptyList() : values.getValues();
      }
docs: Get multiple field values of the same name, split and sorted as a
  {@link QuotedQualityCSV}
  
  @param header The header
  @return List the values in quality order with the q param and OWS
  stripped