Streams Don't Stop When Image Timestamps Don't Match System

[QuentinTorg]

Description
I have a setup where my camera and my host computer are using different time domains (camera time is significantly ahead of computer time). I'm using the jpeg image streamer to stream to a browser. I found that when I close the image stream window in my browser, the subscription was not getting closed.

I have identified the issue as timestamp mismatch. It appears this will be a problem for both ROS1 and ROS2 with the same solution in both

• Library Version: ros1 branch
• ROS Version: ROS1 Noetic
• Platform / OS: Ubuntu 20.04

Steps To Reproduce

• stream image topics that have header in the future
• start web video server node
• subscribe to image topics in the browser
• rostopic info shows web video server subscribed to image topic
• close browser window with image stream

Expected Behavior
rostopic info should show no subscribers for the image topic once the window is closed

Actual Behavior
rostopic info shows that there is still an active subscriber to the image stream

[bjsowa]

Fixed in #173 and #174