code: static int getIndex(byte[] name, byte[] value) {
      int index = getIndex(name);
      if (index == -1) {
        return -1;
      }
  
      // Note this assumes all entries for a given header field are sequential.
      while (index <= length) {
        HeaderField entry = getEntry(index);
        if (!HpackUtil.equals(name, entry.name)) {
          break;
        }
        if (HpackUtil.equals(value, entry.value)) {
          return index;
        }
        index++;
      }
  
      return -1;
    }
docs: Returns the index value for the given header field in the static table.
  Returns -1 if the header field is not in the static table.