Nicer text/* response values

For text response values, it is not very ergonomic to get the text (the response body).

Example

Consider the following API:

openapi: "3.0.0"

info:
  title: Hello World
  version: "1.0"

paths:
  /hello:
    get:
      operationId: getHello
      responses:
        "200":
          description: Get hello
          content:
            text/plain:
              schema:
                type: string
                example: Hello World

Progenitor generates the following code:

#[allow(clippy::all)]
impl Client {
    ///Sends a `GET` request to `/hello`
    pub async fn get_hello<'a>(&'a self) -> Result<ResponseValue<ByteStream>, Error<()>> {
        let url = format!("{}/hello", self.baseurl,);
        #[allow(unused_mut)]
        let mut request = self.client.get(url).build()?;
        let result = self.client.execute(request).await;
        let response = result?;
        match response.status().as_u16() {
            200u16 => Ok(ResponseValue::stream(response)),
            _ => Err(Error::UnexpectedResponse(response)),
        }
    }
}

To integrate this in my code and read the response, I need something like this:

use futures::StreamExt;

async fn test_hello() {
    let client = Client::new("baseurl");
    let resp_val = client.get_hello().await.unwrap();
    let mut stream = resp_val.into_inner_stream();

    let mut bytes: Vec<u8> = Vec::new();
    while let Some(n) = stream.next().await {
        let b = n.unwrap();
        bytes.extend_from_slice(&b);
    }
    let hello = String::from_utf8(bytes).unwrap();
    dbg!("{}", hello);
}

Expected behaviour

That's not very ergonomic. Sure, I know at a high-level that I need to collect the byte stream into a vector. But it still took me a while to figure out the exact types to make it compile...

It would be nice if there were a more obvious API that makes it easier to "just get the body string".

reqwest::Response already has useful methods like text() or json(). But since progenitor's client hides the reqwest::Response from me, I cannot use those.

Alternatively, it would be nice to have an example somewhere that shows how to read such basic text responses.

Version

(cargo-)progenitor 0.7.0

Start with the generated ResponseValue and its into_inner_stream path shown in the issue, then compare the reqwest::Response text() and json() APIs it references. Clarify whether the desired outcome is a simpler text-body API or an example for collecting the stream. Done means the chosen approach makes basic text responses straightforward and is demonstrated clearly.