When the browserperfdash-benchmark script sends the data for a bot to a server like https://browserperfdash.igalia.com the data is assumed to be received now. That is fine for the general use case. But sometimes it is desirable to send data with a different date, for example for the following use cases: Use case 1) - Several boards (for example RPis) are downloading build products from the build server and doing benchmarks. It is not guaranteed that the boards end the testing in order, so it can happen that a board testing WebKit version r12345 ends after the board testing version r12346. Use case 2) - Some data for older versions is missed and you want to setup a bot to test that older versions and then have the data ordered properly on the dashboard. For this use cases the runner should support a timestamp optional parameter that can be used to send the data with a specific date to the server. The server already supports this, so this bug is about implementing it on the runner.