A great, fast supported way is documented here using Azure SQL Geo Replication.
The idea is:
The Sitecore Web DB is put in a geo replication group
You need a new "Shared" DB that all Sitecore instances connect to - purely for the Event Queue, Properties, and Tasks tables.
This way your content data is replicated with the power of Azure SQL, but ...
I have found that, because Experience Editor runs in the context of the site you are looking at, the site definition in config requires the attribute enableWorkflow="true".
<site name="mySite" enableWorkflow="true" ... />
This fixed the issue for me. Hope this helps.