The sequence of service accounts in a delegation chain. Each
service account must be granted the
roles/iam.serviceAccountTokenCreator role on its next
service account in the chain. The last service account in the
chain must be granted the
roles/iam.serviceAccountTokenCreator role on the service
account that is specified in the name field of the
request. The delegates must have the following format:
projects/-/serviceAccounts/{ACCOUNT_EMAIL_OR_UNIQUEID}
The desired lifetime duration of the access token in seconds.
Must be set to a value less than or equal to 3600 (1 hour). If
a value is not specified, the token's lifetime will be set to
a default value of one hour.