Program doesn't see Host Header - go

Question

Trying to proxy a request, and I discovered the host header is not being present in the headers received
UPDATE: as pointed out from one of the answers, I might need the Host field, this doesn't change either, host headers are still not present.
code:
request, err := http.ReadRequest(bufio.NewReader(conn))
if err != nil {
log.Println("Error reading request", err)
return
}
target, err := net.Dial("tcp", request.URL.Host)
if err != nil {
log.Println(host)
log.Println("Error reaching target", err)
}
defer target.Close()
curl command
curl -v localhost:8080
Output:
Trying 127.0.0.1:8080...
* Connected to localhost (127.0.0.1) port 8080 (#0)
> GET / HTTP/1.1
> Host: localhost:3000
> User-Agent: curl/7.79.1
> Accept: */*
>
So host header is present in the curl.
Added a debug step to the program to print headers
fmt.Println("Headers:")
for key, values := range request.Header {
fmt.Printf("%s: %v\n", key, values)
}
Output from program:
Headers:
Accept: [*/*]
User-Agent: [curl/7.79.1]
Still no presence of Host header
Now I tried passing a host header with curl:
curl -v -H 'Host: localhost:3000' localhost:8080
Same output, header present in curl but not on the program

Answer 1

What you want is the Host field of the Request type. From the Godoc:
// For server requests, Host specifies the host on which the
// URL is sought. For HTTP/1 (per RFC 7230, section 5.4), this
// is either the value of the "Host" header or the host name
// given in the URL itself. For HTTP/2, it is the value of the
// ":authority" pseudo-header field.
// It may be of the form "host:port". For international domain
// names, Host may be in Punycode or Unicode form. Use
// golang.org/x/net/idna to convert it to either format if
// needed.
// To prevent DNS rebinding attacks, server Handlers should
// validate that the Host header has a value for which the
// Handler considers itself authoritative. The included
// ServeMux supports patterns registered to particular host
// names and thus protects its registered Handlers.
//
// For client requests, Host optionally overrides the Host
// header to send. If empty, the Request.Write method uses
// the value of URL.Host. Host may contain an international
// domain name.
Host string