Javadoc
Replaces the entry corresponding to the given
key with
toAddlink MailboxACLRights}.
Implementations must return a new unmodifiable instance of
MailboxACL. However, implementations may decide to return this in
case the result would be equal to it.
Implementations must ensure that the result does not contain entries with
empty rigths. E.g. "user1:lr;user2:lrwt".replace("user1",
MailboxACLRights.EMPTY) should return "user2:lrwt" rather than
"user1:;user2:lrwt". The same result should be returned by
"user1:lr;user2:lrwt".replace("user1", null).