code: protected function setFile($file)
      {
          if ($file == $this->file) {
              // no change
              return;
          }
          if ($this->fileHandle) {
              // close existing file
              \fclose($this->fileHandle);
              $this->fileHandle = null;
          }
          $this->file = $file;
          if (empty($file)) {
              return;
          }
          $fileExists = \file_exists($file);
          $this->fileHandle = \fopen($file, 'a');
          if ($this->fileHandle) {
              \fwrite($this->fileHandle, '***** '.\date('Y-m-d H:i:s').' *****'."\n");
              if (!$fileExists) {
                  // we just created file
                  \chmod($file, 0660);
              }
          }
      }
docs: Set file we will write to
  
  @param string $file file path
  
  @return void