telegraf internetspeed plugin doesn't work on 00 and 30 minutes

Now, this is one of the more amusing bugs/problems that I run into recently. If you want to use the integrated inputs.internet_speed plugin in telegraf to monitor your home internet speed, you probably end up with a configuration similar to this one

# Monitors internet speed in the network
  ## Sets if runs file download test
  ## Default: false
  enable_file_download = false
  interval = "30m"

If you do this, then you probably run into issues like the following:

2022-02-02T02:00:00Z E! [inputs.internet_speed] Error in plugin: fetching server list failed: unable to retrieve server list

According to issue#9852 this only happens each hour at :00 and :30 minutes. Probably the servers are overloaded at those times, as everybody is configuring to do speedtest at exact :00 and :30 minutes.

So, I changed the interval to 33m and suddenly it works as expected.

It’s somewhat amusing but still, WTF?!?