Fix lint issues

mtglib/internal/dc/public_config_updater.go

 		resp, err := p.http.Do(req)
 		if err != nil {
 			if resp != nil {
-				io.Copy(io.Discard, resp.Body)
-				resp.Body.Close()
+				io.Copy(io.Discard, resp.Body) //nolint: errcheck
+				resp.Body.Close()              //nolint: errcheck
 			}
 			return fmt.Errorf("cannot fetch url %s: %w", url, err)
 		}

mtglib/internal/dc/public_config_updater_test.go

 	s.responseHandler = func(w http.ResponseWriter) {
 		done = true
 		w.WriteHeader(http.StatusOK)
-		w.Write([]byte(result))
+		w.Write([]byte(result)) //nolint: errcheck
 	}
 	go s.u.Run(s.ctx, s.srv.URL, "tcp4")
 
 	s.responseHandler = func(w http.ResponseWriter) {
 		done = true
 		w.WriteHeader(http.StatusOK)
-		w.Write([]byte(result))
+		w.Write([]byte(result)) //nolint: errcheck
 	}
 	go s.u.Run(s.ctx, s.srv.URL, "tcp4")
 

mtglib/internal/dc/telegram.go

 package dc
 
 import (
-	"context"
 	"fmt"
 	"strings"
 	"sync"
 )
 
 type Telegram struct {
-	ctx      context.Context
 	lock     sync.RWMutex
 	view     dcView
 	preferIP preferIP

mtglib/internal/obfuscation/obfuscator_test.go

 }
 
 func (s *ObfuscatorTestSuite) SetupSuite() {
-	s.SnapshotTestSuite.Setup("", "client-handshake")
+	s.Setup("", "client-handshake")
 
 	secret := mtglib.GenerateSecret("hostname.com")
 	s.secret = &secret

mtglib/proxy.go

 
 	tgConn, err := foundAddr.Obfuscator.SendHandshake(conn, ctx.dc)
 	if err != nil {
-		conn.Close()
+		conn.Close() // nolint: errcheck
 		return fmt.Errorf("cannot perform server handshake: %w", err)
 	}