Function register_streaming_functions_with_watermark 

pub fn register_streaming_functions_with_watermark(
    ctx: &SessionContext,
    watermark_ms: Arc<AtomicI64>,
)

Registers streaming UDFs with a live watermark source.

Same as register_streaming_functions but connects the watermark() UDF to a shared atomic value that Ring 0 updates in real time.

Arguments

• ctx - DataFusion session context
• watermark_ms - Shared atomic holding the current watermark in milliseconds since epoch. Values < 0 mean “no watermark” (returns NULL).