Here are the data structures with brief descriptions:
  gcf_cd_status | CD status packet.The Continuous Data standard (from the CTBTO) requires some additional real-time status updates. These updates are sent in a CD status packet, which is decoded into a struct gcf_cd_status |
| gcf_data_hdr | Header details for a data block |
| gcf_generic_hdr | Generic header details shared by all GCF blocks |
| gcf_status_hdr | Header details for a status block |
 gcf_union_hdr | Header union type for parsing |
