$path = $this->resolveToStoragePath( $virtualUrl );
$params = [ 'src' => $path, 'headers' => $headers, 'options' => $optHeaders ];
+ // T172851: HHVM does not flush the output properly, causing OOM
+ ob_start( null, 1048576 );
+ ob_implicit_flush( true );
+
$status = $this->newGood();
$status->merge( $this->backend->streamFile( $params ) );
+ ob_end_flush();
+
return $status;
}