Async optimization.

[chickenlj]

• Unify Results used on the wire: AsyncRpcResult RpcResult SimpleAsyncRpcResult
• Possible async wrapper. Add dobbu util support for async callable feature. #3113
• Some other possible improvements.

[chickenlj]

Generic support, #3637, done
Filters, #3483, almost done
Attachments, #3620, done
Zipkin, #3576, done, nothing to fix
Provider async, #3650, need to remove async config item.

[carryxyh]

Just for a record:
Maybe we should consider the case when C and P use asynchronous at the same time. Currently, when the interface returns a value of CompletableFuture and uses AsyncContext to start asynchronous in ServiceImpl, it will cause some problems.

[maxiaoguang64]

yes, but we can't know that consumer use async

[carryxyh]

Nope, currently Dubbo's consumer asynchronous depends on the server configuration, so we can of course know if the client is using asynchronous...

[maxiaoguang64]

if user use like this
new Thread(() -> service.method()).start()?

[carryxyh]

In this case, the dubbo framework is treated as a synchronous call. This will not cause any problems.
:)

[maxiaoguang64]

in this picture, i use new Thread(() -> service.method()).start() and service is async

[carryxyh]

I don't know the content on this picture. This issue was created to discuss the problem of asynchronous methods in the dubbo framework(Or asynchronous in the dubbo kernel).

My records are not the same problem as the scene you describe. If there are other problems with dubbo's asynchronous, you should create a complete issue to describe it. Thx.