Erorr reading body using DumpResponseHeadersAndRaw when proxy used

[RamanaReddy0M]

When we read the http response body received via proxy, we get both an error and a response(not empty).

In such cases httputils.DumpResponseHeadersAndRaw(..) return an empty response instead actual response.

Example to reproduce

package main

import (
	"crypto/tls"
	"fmt"
	"net/http"
	"net/url"

	pdhttputil "github.com/projectdiscovery/utils/http"
)

func main() {
	// Set the proxy URL
	proxyURL := "http://127.0.0.1:8081" // Update with your actual Burp Suite proxy URL

	// Create a proxy URL object
	proxy, err := url.Parse(proxyURL)
	if err != nil {
		fmt.Println("Failed to parse proxy URL:", err)
		return
	}

	// Create a custom HTTP transport with proxy settings
	transport := &http.Transport{
		Proxy: http.ProxyURL(proxy),
		TLSClientConfig: &tls.Config{
			InsecureSkipVerify: true, // Ignore SSL certificate verification (for Burp Suite proxy)
		},
	}

	// Create an HTTP client with the custom transport
	client := &http.Client{
		Transport: transport,
	}

	// Create an HTTP request
	req, err := http.NewRequest("GET", "https://www.youtube.com", nil)
	if err != nil {
		fmt.Println("Failed to create request:", err)
		return
	}

	// Send the HTTP request via the Burp Suite proxy
	resp, err := client.Do(req)
	if err != nil {
		fmt.Println("Failed to send request via proxy:", err)
		return
	}
	defer resp.Body.Close()

	//##Expected Behaviour
	// Read the response body using ioutils
	//body, err := ioutil.ReadAll(resp.Body)

	//##Current Behaviour
	// Read the response using pdhttputils
	_, body, err := pdhttputil.DumpResponseHeadersAndRaw(resp)

	// Print the response body
	fmt.Println("Body: ", string(body))
	// Err
	fmt.Println("ERROR: ", err)

}