TUN-8456: Update quic-go to 0.45 and collect mtu and congestion control metrics

vendor/github.com/prometheus/procfs/fs.go

@@ -20,7 +20,8 @@ import (
 // FS represents the pseudo-filesystem sys, which provides an interface to
 // kernel data structures.
 type FS struct {
-	proc fs.FS
+	proc   fs.FS
+	isReal bool
 }
 
 // DefaultMountPoint is the common mount point of the proc filesystem.
@@ -39,5 +40,11 @@ func NewFS(mountPoint string) (FS, error) {
 	if err != nil {
 		return FS{}, err
 	}
-	return FS{fs}, nil
+
+	isReal, err := isRealProc(mountPoint)
+	if err != nil {
+		return FS{}, err
+	}
+
+	return FS{fs, isReal}, nil
 }