code: static String formatTimeout(final CouchbaseRequest request, final long timeout) {
          Map<String, Object> fieldMap = new HashMap<String, Object>();
          fieldMap.put("t", timeout);
  
          if (request != null) {
              fieldMap.put("s", formatServiceType(request));
              putIfNotNull(fieldMap, "i", request.operationId());
              putIfNotNull(fieldMap, "b", request.bucket());
              putIfNotNull(fieldMap, "c", request.lastLocalId());
              putIfNotNull(fieldMap, "l", request.lastLocalSocket());
              putIfNotNull(fieldMap, "r", request.lastRemoteSocket());
          }
  
          try {
              return DefaultObjectMapper.writeValueAsString(fieldMap);
          } catch (JsonProcessingException e) {
              LOGGER.warn("Could not format timeout information for request " + request, e);
              return null;
          }
      }
docs: This method take the given request and produces the correct additional timeout
  information according to the RFC.