SequenceDiagram FR: Allow multiple arrows in the same line/level

[lethefrost]

Proposal

I hope we could be able to make some diagrams containing consecutive arrows between participants in the same level, like the following diagram:

I noticed that someone has asked for this feature for notes but not arrows, so I suppose it's not a duplicate FR. There was a PR(#2746) mentioned in that issue, but seems that it's not merged. #4370 seemed to implement the same feature, but could someone help me understand the syntax to generate this @twpol created in their post, since I couldn't find anything related in the documentation?

Any kind of help is greatly appreciated!

Use Cases

No response

Screenshots

No response

Syntax

No response

Implementation

This is a proposal which I'd love to see built into mermaid by the wonderful community.

[ckhiu]

looks like this was implemented in #4370, but par_over is no longer working correctly now (no rendering error, but messages / arrows are not on the same y position). @jgreywolf Could you verify this please?