Function function_body 

pub async fn function_body<S, A, E>(
    body: S,
    args: A,
    env: &mut E,
) -> Result<BoxFuture<'static, ExitStatus>, S::Error>
where
    S: Spawn<E>,
    E: FunctionFrameEnvironment + SetArgumentsEnvironment + ?Sized,
    E::Args: From<A>,

Creates a future adapter that will execute a function body with the given set of arguments.