It appears as though the CreateDataStream and SendDataStream which are available in the Unity SDK are not available in the web SDK. Is there a method that I can use to send data back and forth between clients across Unity and Web versions of Agora.io?
I notice that the RTM SDK is not available for Unity.
you are correct, DataStream is not available for Web. RTM SDK for Unity is on the product road map and it will soon be released in a month or so. Sit on tight and watch for the product announcement.