DataStoreService does not allow removal of data

[TheSneak]

When the DataStoreService is queried for a key that does not exist, it returns nil. However there is no method for removing a key from the data store to revert to this behavior. Attempting to set the value of the key to nil with SetAsync() results in an error like "second argument is missing or nil." Once a value has been assigned to a key, it cannot then be set to nil.

This is troublesome when the presence or absence of a particular data value in the data store is used to determine game state.