Fix to use chunk.unique_id to check ack
 * unique_id is safe for restarts
 * base64 encoding is escape msgpack miss-decoding
  * by Msgpack encode-decode: \u0005 -> \x05
  * this behavior breaks chunk id check
Fix to assume extend_internal_protocol from other options which uses extended protocols
Fix default ack timeout w/ linux kernel default configuration
Fix to raise error for ACK
 * retry send_data for ack timeout
   * by this behavior, fluentd can try other node for failed chunk
   * by this behavior, user can find badly-configured situation