OptionalauthAuth mode(s) to try. Modes are attempted in order — the first match wins.
AuthModeWithKey for the full syntax including named keys.
OptionalallowUse VerifyCredentialsOptions.auth instead. Kept for
backward compatibility; will be removed in a future major release. When
both are provided, auth wins.
OptionalenvOptional environment overrides (passed through to resolveEnv).
Options for verifyCredentials.