More efficient file upload from URL

[woofyman99]

While the sample code works file from a local file. If you're reading from a URL, it's very inefficient. The sample code here is reading from a URL and is very inefficient.

https://developers.google.com/youtube/v3/code_samples/php#resumable_uploads

It looks like it was pulled directly from the sample code in GitHub

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[ianbarber]

Any chance you could sign in the CLA - link in the bot comment? Understand if not, but we need it for any changes.

[woofyman99]

No problem, done.

[googlebot]

CLAs look good, thanks!

[ianbarber]

Thanks!