Throttling throughput in rsync is actually really simple to do. All the information you need to know is in the man pages for rsync, but it is so very surprising to see how many people asking for an answer on the web.
You may have a need from time to time to rsync some data from one location to another, but you may be concerned of either saturating your link to your remote location or getting a hefty bill at the end of the month for over usage.
This is normally common if you were to be syncing via a VPN or internet uplink.
For example, lets say you have a contract with your internet provider to give you internet connectivity and your contractual arrangement is for 10MB/s. However, your supplier gives you a 1Gbps link on a 95 percentile agreement.
Basically this means you are paying for your 10MB/s, but you won’t be hit with a bill for excess usage unless you go over 10MB/s for more than 5% of your allotted billing period.