New more extensive reliability test for proxy

Hi @Sven, I am placing this discussion in the SER category but it could also be for Gsa Proxy Scraper.
I thinking about this for several days. Every time I test (public) proxies with Bing tests and use them in SER, 90% burns in a few minutes.
They are not that they get banned by the search engine because I do not use them to scrape, the listings are imported.
I know our IP can be banned by proxies after a few uses but in my opinion it is not that, 90% is too much.
I think we should add another test, a test that tests the sending and receiving of data for each proxy.
For the downlnoad, downloading a photo for example would suffice but for the upload? Something must be found.
I also appeal to all members who read this post. What could we use heavily enough to do an upload/download test?
I’m thinking for example is file sharing sites for example … Of course, the test could also be done for download right after.
Of course, an anonymity test to be carried out before or after is mandatory :

A proxy whose upload and download have been tested beforehand would be much less inclined to burn under load.