ChainedFastBackend::getLastWriteTimestamp

protected ChainedFastBackend::getLastWriteTimestamp()

protected function getLastWriteTimestamp() {
  if ($this->lastWriteTimestamp === NULL) {
    $cache = $this->consistentBackend->get(self::LAST_WRITE_TIMESTAMP_PREFIX . $this->bin);
    $this->lastWriteTimestamp = $cache ? $cache->data : 0;
  }
  return $this->lastWriteTimestamp;
}