code: func (s *snapshot) Close() {
  	for _, reg := range s.blockRegistrations {
  		close(reg.Eventch)
  	}
  	for _, reg := range s.filteredBlockRegistrations {
  		close(reg.Eventch)
  	}
  	for _, reg := range s.ccRegistrations {
  		close(reg.Eventch)
  	}
  	for _, reg := range s.txStatusRegistrations {
  		close(reg.Eventch)
  	}
  }
docs: // Close closes all event registrations