@Override
			public String[] profilesToActivate() {
				List<String> result = new ArrayList<String>(delegates.size());
				for (String prefix : delegates.keySet()) {
					ModuleOptions delegate = delegates.get(prefix);
					for (String p : delegate.profilesToActivate()) {
						result.add(qualifyProfile(prefix, p));
					}
				}
				return result.toArray(new String[result.size()]);
			}
The composed module itself never needs to activate profiles. It's the submodules that should. The keys
returned here are special constructs that are decoded by {@link PrefixNarrowingModuleOptions}.
spring-xd-module/src/main/java/org/springframework/xd/module/options/HierarchicalCompositeModuleOptionsMetadata.java