Why no content replacement?

I do a form POST to my controller. I get a TURBO_STREAM request. I respond with a turbo_stream response, which renders a partial with some data. I see the response in my browser.

def create
  # do some stuff to ensure our partial will be happy
  @stuff = "yay"
  respond_to do |format|
    format.turbo_stream { render turbo_stream: turbo_stream.replace("my_target", partial: "goober/gobber", locals: {stuff: @stuff}) }
    format.html { render :index, status: :unprocessable_entity }

What I see in my browser as a response to the POST is the stream from the partial.

<turbo-stream action="replace" target="my_target"><template><h1>Sample Report lalalalal</h1></template></turbo-stream>

My template originally rendered with an element:

 <turbo-stream action="replace" target="my_target"></turbo-stream>

So the browser in not doing anything with the response? What am I doing wrong here? Seems like I should see something like

<h1>Sample Report lalalalal</h1> 

in the DOM… inside that element

never mind… I had actually used a turbo-stream element in my HTML… how dumb was that… I guess the docs confused me. Duh,