(PHP 4 >= 4.3.2, PHP 5)
streamWrapper::stream_flush — Flushes the output
This method is called in response to fflush().
If you have cached data in your stream but not yet stored it into the underlying storage, you should do so now.
This function has no parameters.
Should return TRUE if the cached data was successfully stored (or if there was no data to store), or FALSE if the data could not be stored.
If not implemented, FALSE is assumed as the return value.