TUN-8147: Disable ECN usage due to bugs in detecting if supported

cmd/cloudflared/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"math/rand"
+	"os"
 	"strings"
 	"time"
 
@@ -49,6 +50,9 @@ var (
 )
 
 func main() {
+	// FIXME: TUN-8148: Disable QUIC_GO ECN due to bugs in proper detection if supported
+	os.Setenv("QUIC_GO_DISABLE_ECN", "1")
+
 	rand.Seed(time.Now().UnixNano())
 	metrics.RegisterBuildInfo(BuildType, BuildTime, Version)
 	maxprocs.Set()