* fix `make grpc` on new checkouts
* update proto files
* add some stub
* prototype with fake events
* notifying about events
* pass events
* events are being sent
* transfer headers to filters
* create the “filters” struct
* implement new heads
* PoC of New Heads subscription
* fix keep alive
* fixups for the client
* add “type” to the event
* support header event type on client
* better stage refactor
* fixup for the eth backend
* fixups
* fix tests
* fix tests
* fix linters
* address comments
* remove unused log
