Support chunked streaming of File obj's data

Allow chunked streaming of a File obj's BoxReponse data. This will allow large files to be sent through a web server without overloading memory. The pics below show a custom implementation.

Start by reviewing how a File object's BoxResponse data is currently handled and compare it with the custom implementation shown in the issue image. Done means large files can be sent through a web server in chunks without loading the full response into memory.

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