code: private void extractHeaders(final HttpRequest httpRequest) {
          if (headersToAddToLoggingMappingDiagnosticsContext.size() > 0) {
              final MultiMap<String, String> headers = httpRequest.getHeaders();
              headersToAddToLoggingMappingDiagnosticsContext.forEach(header -> {
                  String value = headers.getFirst(header);
                  if (!Str.isEmpty(value)) {
                      MDC.put(REQUEST_HEADER_PREFIX + header, value);
                  }
              });
          }
      }
docs: Extract headersToAddToLoggingMappingDiagnosticsContext data and put them into the logging mapping diagnostics context.
  
  @param httpRequest httpRequest