code: function visitKeyDependencies(source, meta, cb) {
  		canReflect.eachKey(source.keyDependencies || {}, function(keys, obj) {
  			canReflect.each(keys, function(key) {
  				cb(obj, meta, key);
  			});
  		});
  	}
docs: keyDependencies :: Map<obj, Set<key>>