code: private void addInternalHeaderFields(String name, String value) {
          String key = normalisedHeaderName(name);
          Vector<String> v = getHeaders(key);
          if (v == null) {
              v = new Vector<>();
              mHeaderFields.put(key, v);
          }
  
          if (value != null) {
              v.add(value);
          } else {
              mHeaderFields.remove(key);
          }
      }
docs: Add the header stored in internal hashtable
  
  @param name
  @param value