Elgg\Logger::log PHP Method

    public function log($message, $level = self::NOTICE)
    {
        if ($this->disabled_stack) {
            // capture to top of stack
            end($this->disabled_stack);
            $key = key($this->disabled_stack);
            $this->disabled_stack[$key][] = ['message' => $message, 'level' => $level];
        }
        if ($this->level == self::OFF || $level < $this->level) {
            return false;
        }
        if (!array_key_exists($level, self::$levels)) {
            return false;
        }
        // when capturing, still use consistent return value
        if ($this->disabled_stack) {
            return true;
        }
        $levelString = self::$levels[$level];
        // notices and below never displayed to user
        $display = $this->display && $level > self::NOTICE;
        $this->process("{$levelString}: {$message}", $display, $level);
        return true;
    }

 /**
  * Invalidate the query cache
  *
  * @return void
  */
 protected function invalidateQueryCache()
 {
     if ($this->queryCache) {
         $this->queryCache->clear();
         $this->logger->log("Query cache invalidated", \Elgg\Logger::INFO);
     }
 }