How to print full request text before sending it?

Question

I'm using reqwest to send Post requests to an api behind Cloudflare. The problem is that Cloudflare blocks my requests if it's not in a standard format, even if it deviates slightly from the expected request format (for example, the order of headers matter!).

I tried proxying my requests to BurpSuite to check the full plain text of them and everything was good and Cloudflare didn't block me (Note: BurpSuite is not VPN. It's a local proxy app that lets you view/edit your network traffic!). But without proxy, I only get back a Cloudflare block page. I'm guessing when request goes through proxy, the order of headers changes to the correct format!

Now my question is, How do I print the whole request as text before sending it, without a proxy? And how do I make sure this doesn't happen later?

// this works:
// let proxy = reqwest::Proxy::https("127.0.0.1:8080")?;
// let client = reqwest::Client::builder().proxy(proxy).build()?;

// this doesn't work!
let client = reqwest::Client::builder().build()?;

let mut headers = reqwest::header::HeaderMap::new();

headers.insert("User-Agent", "some text".parse().unwrap());
headers.insert(reqwest::header::ACCEPT, "application/json".parse().unwrap());

let data = "{\"message\": \"Hello\", \"options\": {}}";

let request = client
    .post("https://myAPI.com/api/v1/")
    .headers(headers)
    .body(data);

let response = request.send().await?.text().await?;

println!("{}", response);