Reuse http.Client across requests, and allow caller to provide its own.
Reuse http.Client across requests, and allow caller to provide its own.

Enables connection sharing with http keepalive, and allows callers to
use Go's other http client/transport features like request timeouts.

Azure/azure-sdk-for-go,stubey/azure-sdk-for-go,curoverse/azure-sdk-for-go,marstr/azure-sdk-for-go,Azure/azure-sdk-for-go,lirao/azure-sdk-for-go,colemickens/azure-sdk-for-go,Azure/azure-sdk-for-go,lirao/azure-sdk-for-go,stubey/azure-sdk-for-go,Azure/azure-sdk-for-go,garimakhulbe/azure-sdk-for-go,curoverse/azure-sdk-for-go,marstr/azure-sdk-for-go,marstr/azure-sdk-for-go