code: @Override
      public long getHeaderId(int position) {
          if(position < getItemCount()) {
              Change data = getItem(position);
              for (int i=0; i<mChangeLog.versions.size(); i++) {
                  Version version = mChangeLog.versions.get(i);
                  if (version.changes.contains(data)) {
                      return i;
                  }
              }
          }
  
          return -1;
      }
docs: *********************************************************************************************
  
  Sticky Header Methods