docs: public synchronized void init(ImageLoaderConfiguration configuration) {
  		if (configuration == null) {
  			throw new IllegalArgumentException(ERROR_INIT_CONFIG_WITH_NULL);
  		}
  		if (this.configuration == null) {
  			L.d(LOG_INIT_CONFIG);
  			engine = new ImageLoaderEngine(configuration);
  			this.configuration = configuration;
  		} else {
  			L.w(WARNING_RE_INIT_CONFIG);
  		}
  	}