BusyBox speed test and optimization

This should be a relatively simple two part solution to a problem. 1: Need to run an occasional speed test from a bash script on busybox. The results must be in Mbps and can be written to a local file. 2: Need to use a service that will not block the device if the user wants to run many tests every day. Service must allow consumer and commercial use for free. Perhaps even using more than one service to compare against. Since we are using busybox in many of the applications we build, it will be our standard which means there may be sever space limitations. We will have to do some testing with you to determine the best solution which will work on most of our devices. Do a good job on this and I will definitely continue calling upon you for other items.