features [2]: a (int64) , b (int64)

indexes [2]: x (int64) , y (str_)

events: 5

index values: 2

memory usage: 1.2 kB

index ( x: 1 , y: hello ) with 3 events

timestamp	a	…
0.1	1	…
…	…	…
0.3	3	…

… (1 more indexes not shown)