buf.position(saved_position);
buf.get(header_buffer, 0, header_length);
int computed_checksum = Checksum.fletcher32(header_buffer, 0,
header_length);
if (computed_checksum != header_checksum)
throw new HypertableException(Error.COMM_HEADER_CHECKSUM_MISMATCH);
buf.position(saved_position + header_length);
}