if (!stream->stream_header.empty()) {
metacube2_block_header hdr;
memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
hdr.size = htonl(stream->stream_header.size());
hdr.flags = htons(METACUBE_FLAGS_HEADER);
hdr.csum = htons(metacube2_compute_crc(&hdr));
if (!stream->stream_header.empty()) {
metacube2_block_header hdr;
memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
hdr.size = htonl(stream->stream_header.size());
hdr.flags = htons(METACUBE_FLAGS_HEADER);
hdr.csum = htons(metacube2_compute_crc(&hdr));