Have you reviewed data-intensive architectures? I've found that book quite useful.
I'm just talking out my butt right now but I think fundamentally, a stream is just a chunk of data lifted from persist into memory. I imagine a cursor process traversing some bytes in a file, and then lifting some of those bytes into memory, and sending that memory over network.
Yes, however I think there's a lot more complexity in modern steaming architectures: event sourcing, concurrency, eventual consistency, pub-sub, queueing, event handlers, microservices, stateless messages, data lakes - to name a few. I would also be interested in a resource that tackles major concepts here.
I'm just talking out my butt right now but I think fundamentally, a stream is just a chunk of data lifted from persist into memory. I imagine a cursor process traversing some bytes in a file, and then lifting some of those bytes into memory, and sending that memory over network.