lifetime property Null safety
The desired lifetime duration of the access token in seconds.
By default, the maximum allowed value is 1 hour. To set a lifetime of up
to 12 hours, you can add the service account as an allowed value in an
Organization Policy that enforces the
constraint. See detailed instructions at
https://cloud.google.com/iam/help/credentials/lifetime If a value is not
specified, the token's lifetime will be set to a default value of 1 hour.