Values.SendMessageContentBlockStopEventSourceEvent emitted when a content block is complete
type nonrec t = {index : Integer.t option;Zero-based index of the content block
*)type_ : String_.t option;The type of content in this block
*)text : String_.t option;The accumulated complete content text
*)last : Boolean.t option;Whether this is the final content block in the response
*)sequenceNumber : Integer.t option;Event sequence number
*)}