while debugging our code-base we sometimes run into problems which dont occur in the real-world because of the debugger halting the program and certain timeouts occur.

as discussed on twitter https://twitter.com/markusstaab/status/810892163210944513

use case1)
we use a non-blocking file-session handler which is required as phps native handler will LOCK the session on parallel requests without recovering, which can easily be exploited as a (D)DOS vector. see https://bugs.php.net/bug.php?id=72345
when debugging the file-handlers session-timeout will trigger a exception as the timout happens because of the debugger not progressing further.

use case 2)
we monitor our systems request rendertime using $_SERVER['REQUEST_TIME_FLOAT']. as the programm does not progress when halting with the debugger this monitoring also reports false-positives as requests are indentified as beeing slow.

in case we would have a userland api we could whitelist those requests too make sure no timeout occurs or no monitoring alert will happen.