Integrating Mixpanel SDK to Associate Anonymous IDs with Custom IDs

Hi Team I am logged out right now and doing some actions on the site and that data is flowing under anonymous ID say id1 and as soon as I logged in, I want to set my custom ID say CID against id1 and all the events flown under id1 should be tagged to CID. Now, when I am moving to another browser and doing some actions under anonymous ID say id2 and as soon as I logged in, I want to pass on all the events moved from id2 to CID How can I achieve this from mixpanel sdk or api?