URLRequest debugging - http://www.gentlebytes.com/blog/2018/02/28/request-debugging/

URLRequest-extention

extension URLRequest {

    public var curlString: String {
        // Logging URL requests in whole may expose sensitive data,
        // or open up possibility for getting access to your user data,
        // so make sure to disable this feature for production builds!
        #if !DEBUG
            return ""
        #else
            var result = "curl -k "

            if let method = httpMethod {
                result += "-X \(method) \\\n"
            }

            if let headers = allHTTPHeaderFields {
                for (header, value) in headers {
                    result += "-H \"\(header): \(value)\" \\\n"
                }
            }

            if let body = httpBody, !body.isEmpty, let string = String(data: body, encoding: .utf8), !string.isEmpty {
                result += "-d '\(string)' \\\n"
            }

            if let url = url {
                result += url.absoluteString
            }

            return result
        #endif
    }
}


Usage
And log it:

let request = ...
print("\(request.curlString)")