code: public void invokeNotification(String methodName, Object argument, OutputStream output) throws IOException {
  		writeRequest(methodName, argument, output, null);
  		output.flush();
  	}
docs: Invokes the given method on the remote service passing
  the given argument without reading or expecting a return
  response.
  
  @param methodName the method to invoke
  @param argument   the argument to pass to the method
  @param output     the {@link OutputStream} to write to
  @throws IOException on error
  @see #writeRequest(String, Object, OutputStream, String)