How to use the payload's timestamp?

We receive JSON-encoded data like
{"data":\[{"n":1234,"s":"abcd","t":1630543365507,"x":0.5678}],"type":"sample"}
where "t" is the (UNIX epoch milliseconds) time at which this sample was collected.
How can we use that as the Timestream timestamp?

Timestream's Product FAQ (https://aws.amazon.com/timestream/faq/?loc=5#Data_ingestion) says it "uses the timestamp of the time series event being written into the database."
The Developer Guide (https://docs.aws.amazon.com/timestream/latest/developerguide/concepts.html) says "Timestamp - Indicates when a measure was collected for a given record."
The Developer Guide (https://docs.aws.amazon.com/timestream/latest/developerguide/data-ingest.html) says "Data ordered by timestamps has better write performance"

What do the ingested data's timestamps matter, if Timestream will apply timestamps corresponding to the time they're written into the database?

A Timestream developer forum thread (https://forums.aws.amazon.com/thread.jspa?threadID=329388) refers to an IoT developer forum thread (https://forums.aws.amazon.com/thread.jspa?messageID=959502) in which the IoT feature Timestream Rule Action (https://docs.aws.amazon.com/iot/latest/developerguide/timestream-rule-action.html) was implemented (according to @manbeenaws) to specify an arbitrary value (i.e. a timestamp specified in the MQTT payload) as the Timestream timestamp.

Is there a way to use a payload value as the Timestream timestamp, if the data don't arrive via IoT?

Edited by: bobsut on Sep 1, 2021 11:44 AM

Edited by: bobsut on Sep 1, 2021 12:35 PM