Future Work: Replace synchronous block delivery with asynchronous

[0x19]

Right now block production from sequencers is slow. It can produce only 1 block in 10-15s interval. In order to change that, when we are submitting blocks to avail, we should wait only for initial block acceptance status. However, that feature is not working correctly in the go substrate library github.com/centrifuge/go-substrate-rpc-client/v4 and needs to be resolved.

Following line of code would need to be replaced:
https://github.com/availproject/op-evm/blob/main/consensus/avail/sequencer.go#L517

[cpp-phoenix]

@0x19 Please assign it to me

[0x19]

@cpp-phoenix assigned.

[cpp-phoenix]

Hey @0x19, I've narrowed down the issue to below line of code. Can you please help me understand what exactly is the issue with the gsrpc library here. Which status should depict initial block acceptance and what are we getting currently?

for {
		select {
		case status := <-sub.Chan():
			_, err := dstatus.MarshalJSON()
			if err != nil {
				panic(err)
			}
			// NOTE: See first line of this function for supported extrinsic status expectations.
			switch {
			case dstatus.IsFinalized && status.IsFinalized:
				return nil
			case dstatus.IsInBlock && status.IsInBlock:
				return nil
			case dstatus.IsReady && status.IsReady:
				return nil
			default:
				if status.IsDropped || status.IsInvalid {
					return fmt.Errorf("unexpected extrinsic status from Avail: %#v", status)
				}
			}
		case err := <-sub.Err():
			// TODO: Consider re-connecting subscription channel on error?
			return err
		}
	}