revert #4583 (#4606)

This reverts commit 500d18b6c6.

internal/staticsources/rtmp/source.go

@@ -18,8 +18,6 @@ import (
 	"github.com/bluenviron/mediamtx/internal/stream"
 )
 
-var timeNow = time.Now
-
 // Source is a RTMP static source.
 type Source struct {
 	ReadTimeout  conf.Duration
@@ -88,8 +86,7 @@ func (s *Source) runReader(ctx context.Context, u *url.URL, fingerprint string)
 	}
 
 	r := &rtmp.Reader{
-		Conn:    conn,
-		TimeNow: timeNow,
+		Conn: conn,
 	}
 	err = r.Initialize()
 	if err != nil {