What is the difference between a “qualified stream” and a “non-qualified stream”?
Based on the API Compatibility Matrix document that, the Qualified Stream is the "Tunnel Stream"
### What is a Tunnel Stream? ###
A tunnel stream is a private stream with additional behaviors, such as end-to-end line of sight for authentication and guaranteed delivery. Tunnel streams are founded on the private streams concept, and the Enterprise Transport API establishes them between consumer and provider endpoints (passing through any intermediate components, such as Refinitiv Real-Time Distribution System or a Refinitiv Real-Time Edge Device).
When creating a tunnel, the consumer indicates any additional behaviors to enforce, which is exchanged with the provider application end point. The provider end-point acknowledges creation of the stream as well as the behaviors that it will enforce on the stream. After the stream is established, the consumer can exchange any content it wants, though the tunnel stream will enforce behaviors on the transmitted content as negotiated with the provider.
The example of a tunnel stream usage is the RTSDK consumer application needs to contribute data to Refinitiv Contributions Channel (RCC) via the tunnel stream.
This tunnel stream feature is available in the RTSDK (ETA, ETA Reactor, and EMA APIs) only, not the WebSocket API.
About the "Non-Qualified Stream", it is a normal stream between the consumer and provider.