可以在Actix Actor中通过发送异步消息的方式调用异步函数并处理HTTP请求。具体的解决方法如下所示：

use actix::{Actor, AsyncContext, Context, Handler};
use actix_web::{client::Client, Error};

struct HttpActor {
    client: Client,
}

impl Actor for HttpActor {
    type Context = Context;
}

struct HttpRequestMessage(String);

impl Message for HttpRequestMessage {
    type Result = Result;
}

impl Handler for HttpActor {
    type Result = Result;

    fn handle(&mut self, msg: HttpRequestMessage, ctx: &mut Context) -> Self::Result {
        let url = msg.0;
        let fut = self.client.get(&url).send().map_err(Error::from).and_then(|response| {
            response
                .body()
                .limit(1024 * 1024) // limit size of the response body
                .map_err(Error::from)
        });
        ctx.spawn(fut.into_actor(self).map(|res, _act, _ctx| res));
        Ok(String::from("Request sent."))
    }
}

#[derive(Debug)]
struct HttpResponse(String);

impl Message for HttpResponse {
    type Result = Result<(), ()>;
}

struct HttpResponseActor;

impl Actor for HttpResponseActor {
    type Context = Context;
}

impl Handler for HttpResponseActor {
    type Result = Result<(), ()>;

    fn handle(&mut self, msg: HttpResponse, _ctx: &mut Context) -> Self::Result {
        println!("Response received: {}", msg.0);
        Ok(())
    }
}

fn main() {
    let sys = actix_rt::System::new("test");

    let http_client = Client::new();
    let http_actor = HttpActor { client: http_client };

    let http_response_actor = HttpResponseActor.start();

    let url = String::from("https://www.rust-lang.org");
    let http_request_message = HttpRequestMessage(url.clone());
    let response = http_actor.send(http_request_message);
    response.into_actor(http_response_actor).map(|res, _act, ctx| {
        if let Err(e) = res {
            println!("Error: {}", e);
        } else {