|Default Value||Data Type||Required|
This option specifies how the driver obtains or provides the credentials for OAuth 2.0 authentication.
0: The driver uses service-based OAuth authentication (see Using a Google Service Account).
1: The driver uses user-based OAuth authentication (see Using a Google User Account).
2: The driver uses pre-generated tokens for authentication (see Using Pre-Generated Access and Refresh Tokens).
3: The driver uses Application Default Credentials for authentication (see Using Application Default Credentials).