code: public static <C, A> Callbacks<C, A> callbacks(Class<C> callbackType,
  			Collection<? extends C> callbackInstances, A argument,
  			Object... additionalArguments) {
  		Assert.notNull(callbackType, "CallbackType must not be null");
  		Assert.notNull(callbackInstances, "CallbackInstances must not be null");
  		return new Callbacks<>(callbackType, callbackInstances, argument,
  				additionalArguments);
  	}
docs: Start a call to callback instances, dealing with common generic type concerns and
  exceptions.
  @param callbackType the callback type (a {@link FunctionalInterface functional
  interface})
  @param callbackInstances the callback instances (elements may be lambdas)
  @param argument the primary argument passed to the callbacks
  @param additionalArguments any additional arguments passed to the callbacks
  @param <C> the callback type
  @param <A> the primary argument type
  @return a {@link Callbacks} instance that can be invoked.