OptionalidThe id of the function call. This must be sent back in the associated FunctionResponse.
This property is only supported in the Gemini Developer API (GoogleAIBackend).
When using the Gemini Developer API (GoogleAIBackend), this property will be
undefined.
A predicted FunctionCall returned from the model that contains a string representing the FunctionDeclaration.name and a structured JSON object containing the parameters and their values.