code: public long callAsync(XMLRPCCallback listener, String methodName, Object... params) {
  		long id = System.currentTimeMillis();
  		new Caller(listener, id, methodName, params).start();
  		return id;
  	}
docs: Asynchronously call a remote procedure on the server. The method must be
  described by a method  name. If the method requires parameters, this must
  be set. When the server returns a response the onResponse method is called
  on the listener. If the server returns an error the onServerError method
  is called on the listener. The onError method is called whenever something
  fails. This method returns immediately and returns an identifier for the
  request. All listener methods get this id as a parameter to distinguish between
  multiple requests.
  
  @param listener A listener, which will be notified about the server response or errors.
  @param methodName A method name to call on the server.
  @param params An array of parameters for the method.
  @return The id of the current request.