Arithmetic operation on 2 time based fields

let’s say Elastic has this documents:
_index:a
_type:b
_id:c
{ …
timestamp_1:2019-05-03T11:36:55Z,
timestamp_2:2019-05-03T13:51:24Z,
…}

how to write query in grafana to perform subtract timestamp_1 field from timestamp_2 field to get time length?

i think this related to this feature request. do you know if now it’s supported?

[Feature request] Allow Script filed with timestamp #8899