Getting JSON post request body in App Platform serverless Go function

I have an App Platform instance with serverless Go functions as below

type Request struct {
	JWT string `json:"jwt"`
}

type Response struct {
	StatusCode int               `json:"statusCode,omitempty"`
	Headers    map[string]string `json:"headers,omitempty"`
	Body       string            `json:"body,omitempty"`
}

func Login(in Request) (*Response, error) {
    ...
}

the Request type seems to only be URL parameters when I try to use it.

Is there any way to get the body of the post request or headers?