interface EmptyContentErrorParamsThe prompt-level blockReason, when the request was rejected before
any candidate was generated at all.
The candidate's finishReason, when available (e.g. "SAFETY",
"RECITATION", "MALFORMED_FUNCTION_CALL", "MAX_TOKENS", "OTHER").
Optional custom error message. If not provided, a default message is
generated from finishReason/blockReason.