public function close()
    {
        if ($this->isClosed) {
            // TODO: Should this be an error condition? e.g. BadMethodCallException
            return;
        }

        if (strlen($this->buffer) > 0) {
            $this->insertChunkFromBuffer();
        }

        $this->fileCollectionInsert();
        $this->isClosed = true;
    }