This module allows to throttle file upload speed, for debugging / testing purposes.

phpize
./configure
make
make install

; load throttle module
extension=throttle.so
; speed limit, in bytes
throttle.speed=10240
; log debug infos
throttle.debug=0

Both settings are per-dir and can be overriden on a per-directory basis; for example in an Apache's .htaccess:

php_value throttle.speed 2048