Non-zero provider-specific values that disable SDK retries.
google-genai counts total attempts, not retries. Before 1.68.0 it read zero
as unset and restored its own five-attempt default; from 1.68.0 on it coerces
zero to one (_api_client._retry_args), so zero and one now behave alike. One is
sent because it disables retries on both, and it is the only value that means
"the initial request only" on every version.
Other registered providers count retries, so zero disables them.
