Failed to use Openapi SDK in Actix-web async handler

[francescobianco]

Description:
Trying to call the Openapi SDK client from an Actix-web async handler:

async fn get_user() -> impl Responder {
    let client = openapi_sdk::Client::new("API_KEY");
    let user = client.get_user(123).await.unwrap();
    HttpResponse::Ok().json(user)
}

Getting: error: future cannot be sent between threads safely.
Probably related to Actix’s runtime. How should we properly integrate Openapi SDK async calls with Actix?