packet.length = sizeof(struct sr_datafeed_header);
packet.payload = &header;
header.feed_version = 1;
gettimeofday(&header.starttime, NULL);
header.samplerate = sigma->cur_samplerate;
packet.length = sizeof(struct sr_datafeed_header);
packet.payload = &header;
header.feed_version = 1;
gettimeofday(&header.starttime, NULL);
header.samplerate = sigma->cur_samplerate;