A Hudi `timeline instant` consists of the following components
- def~instant-action: Type of action performed on the def~table
- def~instant-time: typically a timestamp (e.g: 20190117010349), which monotonically increases in the order of action’s begin time.
- instant state: current state of the def~timeline
- Each instant also has metadata either in avro or json format, that describes in detail the state of the action, at its state on that instant time