Websocket RPC support

[4lve]

Would be cool if websocket rpc support was added, or atleast a setting in umi.rpc.call

[4lve]

Found a temp fix, using

(umi.rpc as any).connection as Connection

Don't use this in production code tho as in the future the rpc is going to be rewritten.

[lorisleiva]

Yeah Umi current lacks a RpcSubscriptionsInterface but my plan is to add support for it when I update Umi to be compatible with the new web3.js.

Thanks for raising an issue though. I'll leave it open until there's an official solution for it.

[SS7896]

Would be cool if websocket rpc support was added, or atleast a setting in umi.rpc.call