docs: public static Result<Jwt> populateCCToken(final Jwt jwt) {
          boolean isInRenewWindow = jwt.getExpire() - System.currentTimeMillis() < jwt.getTokenRenewBeforeExpired();
          logger.trace("isInRenewWindow = " + isInRenewWindow);
          //if not in renew window, return the current jwt.
          if(!isInRenewWindow) { return Success.of(jwt); }
          //the same jwt shouldn't be renew at the same time. different jwt shouldn't affect each other's renew activity.
          synchronized (jwt) {
              //if token expired, try to renew synchronously
              if(jwt.getExpire() <= System.currentTimeMillis()) {
                  Result<Jwt> result = renewCCTokenSync(jwt);
                  if(logger.isTraceEnabled()) logger.trace("Check secondary token is done!");
                  return result;
              } else {
                  //otherwise renew token silently
                  renewCCTokenAsync(jwt);
                  if(logger.isTraceEnabled()) logger.trace("Check secondary token is done!");
                  return Success.of(jwt);
              }
          }
      }