code: public Map<String,List<String>> getRequestProperties() {
          if (connected)
              throw new IllegalStateException("Already connected");
  
          if (requests == null)
              return Collections.EMPTY_MAP;
  
          return requests.getHeaders(null);
      }
docs: Returns an unmodifiable Map of general request
  properties for this connection. The Map keys
  are Strings that represent the request-header
  field names. Each Map value is a unmodifiable List
  of Strings that represents the corresponding
  field values.
  
  @return  a Map of the general request properties for this connection.
  @throws IllegalStateException if already connected
  @since 1.4