Currently, to register system view we need at least to actions:
- Register walker for a system view class
- Register system view itself for a given class
There is a map maintained to bind the attribute walker and system view class.
Sometimes walker registration code and system view registration code are located in different parts of Ignite.
But in most cases, there is 1:1 relation between attribute walkers and system views. We don't need to maintain additional structures and do additional actions to find a walker by system view class, we can bind walker to system view itself and can do it atomically.
Moreover, in the current implementation, there is impossible to use different walkers for one system view class (for example when we want to create two views with the same system view class, but with different columns set)