Enhance Function_calling.ipynb cookbook

[NickEfthymiou]

Description of the feature request:

Add example of Parallel function calling in the last section of cookbook/quickstarts
/Function_calling.ipynb

The last section of the cookbook demonstrates the parallel-calling feature when there are no dependencies between arguments to be supplied to function tools and results from previous function tools. That is a good starting point.

Many applications have partial dependencies. In other words, there are situations where, say, three functions can be requested by the model in parallel (because there are no dependencies between them) and two more functions are available to the model which can not yet be called because their arguments depend on results from one of the previously mentioned three functions.

It will be helpful to describe how this flow will be implemented even if it is currently not working.

See also
https://discuss.ai.google.dev/t/function-calling-in-gemini-1-5-pro-latest-are-multiple-functioncall-in-the-same-response-a-positive-development/632

What problem are you trying to solve with this feature?

Clarify the development direction for developing with function tools

Any other information you'd like to share?

Update issue
#94
It has been implicitly answered (and it would have been helpful if it had been actually answered before the May 15th code drop).