I have sent a text to streams, can i know the length of the video , before the video response

I am using streams endpoint

I have one more question , the api request is successfully hit , but i am getting the response ,

and the length of stats array , i am getting 3-4 when i am not getting response

, as per compared when it sends data correctly it is 6-7 or 8-9

What may be the expected reason for this ?