'Timeout': Sets how many milliseconds to wait for a new frame until sending is considered to be stopped
If rendering every frame this can be very low. Default is 1000 to allow stalls due to loading, etc. When set to 0 the image will stay up even when Unity is ended (until the receiving application also ends).
Unfortunately, setting the value to zero immediately clears the the image.
In README.md, you said
Unfortunately, setting the value to zero immediately clears the the image.