docs: public User login(final String username,
              final String password) throws IOException, GroovesharkException {
          JsonNode node = sendRequest(new RequestBuilder("authenticateUser", true) {
  
              @Override
              void populateParameters(Session session, ObjectNode parameters) {
                  parameters.put("username", username);
                  parameters.put("password", password);
              }
          });
          // Success: the session that created this request is now authenticated,
          // so we can mark is as such.
          User user = new User(this, username, password, node);
          session.setAuthenticated(user);
          return user;
      }