public static boolean isEventStream(Shape shape) {
        return shape.isUnionShape() && shape.hasTrait(ID);
    }
Determines whether a given shape is an event stream.

@param shape The shape to check.
@return True if the shape is a union and has the streaming trait.
smithy-model/src/main/java/software/amazon/smithy/model/traits/StreamingTrait.java