private function insertChunk($data)
    {
        $chunkDocument = [
            'files_id' => $this->_documentId,
            'n' => $this->chunkCount,
            'data' => new Binary($data, Binary::TYPE_GENERIC),
        ];

        hash_update($this->_hashContext, $data);

        $this->collection->getChunkCollection()->insert($chunkDocument);
        $this->length += StringHelper::byteLength($data);
        $this->chunkCount++;
    }