code: public MessagingBuilder register(MessagingConfigurer configurer, int priority) {
  		configurers.add(new PrioritizedConfigurer(priority, configurer));
  		return this;
  	}
docs: Registers a configurer with a priority. Configuration order may be
  important. The priority is used to apply configurers in order. The
  configurer with highest priority (applied first) has the greatest value.
  
  The configurer is applied on a this builder instance to configure it
  (when {@link #configure()} is called).
  
  <p>
  When using {@link #standard()} and {@link #minimal()} factory methods,
  the list of configurers are automatically loaded from the classpath and
  registered. The priority is indicated through the {@link ConfigurerFor}
  annotation.
  
  
  @param configurer
  the configurer to register
  @param priority
  the configurer priority
  @return this instance for fluent chaining