Return id when `track` is executed and add `get(id)` to retrieve the event logged

[dani69654]

Hello devs,

• It would be extremely useful is track() returns a unique ID;

• Then also have a get(ID) that fetches an event.
  Atm it is not possible to add tests to verify if an event has been created with the right details.

[ArsalImam]

Mixpanel's backend only returns 0 & 1 in response. It doesn't reveal the actual event id (or any other information) in the response of /track API. Moreover, I think, they didn't offer any API to retrieve any event details by id.

Documentation LInk: https://developer.mixpanel.com/reference/track-event