code: private DeltaIteration<ST, WT> setResources(ResourceSpec resources) {
  		Preconditions.checkNotNull(resources, "The resources must be not null.");
  		Preconditions.checkArgument(resources.isValid(), "The values in resources must be not less than 0.");
  
  		this.minResources = resources;
  		this.preferredResources = resources;
  
  		return this;
  	}
docs: Sets the resources for the iteration, and the minimum and preferred resources are the same by default.
  The lower and upper resource limits will be considered in dynamic resource resize feature for future plan.
  
  @param resources The resources for the iteration.
  @return The iteration with set minimum and preferred resources.