Aggregate operations into a single work request

[spekulant]

At the moment, we run 3 queues

save   chan ItemRequest
fetch  chan Request
delete chan Request

func (s *KVStore) loop() {
	for {
		select {
		case setRequest := <-s.save:
			// set process
		case getRequest := <-s.fetch:
			// get process
		case delRequest := <-s.delete:
			// del process
                }
        }
}

This leads to a situation where save has bigger priority than fetch and might behave unexpectedly in corner case scenarios.

In order to further strengthen thread safety, it would be good to run a select loop on a single channel like a work unit.

func (s *KVStore) loop() {
	for {
		select {
		case request := <-s.operations:
			// unified process
                }
        }
}

Shape of the Request in operations chan Request is yet to be decided as mistakes here might lead to type safety issues. Obviously we dont want to trade thread safety for type safety.

Issue open for thoughts