While discussing with Stelios, I realised that it is useful in some circumstances to receive a notification in case of a 1-1 transition.
This diff captures the design improvements
https://github.com/infinispan/infinispan/wiki/Continuous-query-design-and-indexless-queries/_compare/fd92aa7b0f95fc117b5b6ea9a84bb61c16b3be7e...b77fc2907bac26c53d631dbb35a67c9e1d428656
Emmanuel