There are two important restrictions to using indexers. First,because an indexer does
not define a storage location, a value produced by an indexer cannot be passed as a ref or
out parameter to a method. Second, an indexer must be an instance member of its class; it
cannot be declared static.
1. why we can't pass produced value by indexer as ref or out parameter to an method?
2. why indexers can not be static?