This API is incredibly slow

This API is incredibly slow. I'm talking about minutes to provides cost for a single ResourceGroup with a dozen objects.

Perhaps some guidance could be provided with the parameters to help define what exactly will improve the speed of this API?

Also, there's throttling that returns a 429 if we try to run concurrent requests...

[Enter feedback here]

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#### Document Details

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* ID: e05c0768-9cfc-3b78-4f39-70a8c1f0b6bd
* Version Independent ID: b5e5d8fa-e84c-408a-3f49-19d245563abd
* Content: [az consumption usage](https://docs.microsoft.com/en-us/cli/azure/consumption/usage?view=azure-cli-latest)
* Content Source: [latest/docs-ref-autogen/consumption/usage.yml](https://github.com/MicrosoftDocs/azure-docs-cli/blob/master/latest/docs-ref-autogen/consumption/usage.yml)
* Service: **cost-management-billing**
* GitHub Login: @rloutlaw
* Microsoft Alias: **routlaw**