code: String compact(final String json) throws IOException {
          final StringWriter output = new StringWriter(json.length());
          final JsonFactory factory = mapper.getFactory();
          final JsonParser parser = factory.createParser(json);
  
          final JsonGenerator generator = factory.createGenerator(output);
  
          // https://github.com/jacoco/jacoco/wiki/FilteringOptions
          //noinspection TryFinallyCanBeTryWithResources - jacoco can't handle try-with correctly
          try {
              while (parser.nextToken() != null) {
                  generator.copyCurrentEvent(parser);
              }
          } finally {
              generator.close();
          }
  
          return output.toString();
      }
docs: TODO json.replace("\n", "") would cover our biggest use case