Internal Streaming Api
@Target(allowedTargets = [AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.PROPERTY ] )
Marks streaming-capability types as internal SPI. The core and tests may use them; they are not part of the public agent API and may change without notice. Kotlin callers must opt in with @OptIn(InternalStreamingApi::class).
Note: opt-in is enforced by the Kotlin compiler only; Java callers are not checked.