How to reponse a binary data type?

[AmazingPangWei]

As title described, I've tried this:

// @Summary MyBinary
// @Produce octet-stream
// @Success 200 {string} binary "mybinary"
// @Router /myapis/myBinary [post]

and swagger.json like this:

        "/myapis/myBinary": {
            "post": {
                "produces": [
                    "application/octet-stream"
                ],
                "summary": "MyBinary",
                "responses": {
                    "200": {
                        "description": "mybinary",
                        "schema": {
                            "type": "string"
                        }
                    }
                }
            }
        }

As far as I know, according to the documentation of OpenAPI, schema.format should be binary, but I don't know how to specify it.