code: public String headerOut(String name)
    {
      ArrayList<String> keys = _headerKeysOut;
  
      int headerSize = keys.size();
      for (int i = 0; i < headerSize; i++) {
        String oldKey = keys.get(i);
  
        if (oldKey.equalsIgnoreCase(name)) {
          return (String) _headerValuesOut.get(i);
        }
      }
  
      /*
      if (name.equalsIgnoreCase("content-type")) {
        throw new UnsupportedOperationException();
        //return request().getContentType();
      }
      */
  
      if (name.equalsIgnoreCase("content-length")) {
        return _contentLengthOut >= 0 ? String.valueOf(_contentLengthOut) : null;
      }
      
      if (name.equalsIgnoreCase("content-type")) {
        return _contentTypeOut;
      }
  
      return null;
    }
docs: Returns the value of an already set output header.
  
  @param name name of the header to get.