@Override
  protected void decodePayload(byte[] pl) {
    final int flags = decodeInt(pl, 0);
    final byte[] data = new byte[pl.length - EXTRA_HDR_LEN - keyLen];
    System.arraycopy(pl, (EXTRA_HDR_LEN + keyLen), data, 0,
      pl.length - EXTRA_HDR_LEN - keyLen);
    ReplicaGetOperation.Callback gcb =
      (ReplicaGetOperation.Callback) getCallback();
    gcb.gotData(key, flags, data);
    getCallback().receivedStatus(STATUS_OK);
  }
Length of the extra header stuff for a GET response.
src/main/java/net/spy/memcached/protocol/binary/ReplicaGetOperationImpl.java