code: public static String toOriginal(Span span) {
  
          String id = span.getId();
  
          if (span.clientSpan()) {
              int suffixIndex = id.lastIndexOf(CLIENT_ID_SUFFIX);
              if (suffixIndex > 0) {
                  id = id.substring(0, suffixIndex);
              }
          }
  
          return id;
      }
docs: Reverse method to the {@link SpanUniqueIdGenerator#toUnique(Span)} to generate original
  id from the unique id.
  
  @param span Span with unique id.
  @return Original id of the span.