DriveItem Copy endpoint has incorrect return type

[hazzinator1]

Describe the bug
The current implementation of Copy endpoint for drive items is incorrect, as it tries to return a DriveItem as the result. The Graph API documentation shows that it instead sends back a URI in the Location response header.
#768 seemed to show that it was possible to access the response headers, however this ability is either hidden to me or has been changed and is therefore no longer accessible.

To Reproduce

var copyResponse = this.GraphServiceClient
                .Drives[driveId]
                .Items[driveItemId]
                .Copy.PostAsync(copyRequestBody);

Expected behavior
Rather than trying to find "workarounds" to get the Location URI, why can't the Copy method just return the URI as the result?

No other relevant information

[andrueastman]

Thanks for raising this @hazzinator1

At the moment this is possible to do as below.
https://github.com/microsoftgraph/msgraph-sdk-dotnet/blob/dev/docs/upgrade-to-v5.md#native-response-object

            var nativeResponseHandler = new NativeResponseHandler();
            await graphClient.Drives["drive-id"]
                .Items["item-id"]
                .Copy.PostAsync(copyRequestBody,
                    requestConfiguration => requestConfiguration.Options.Add(new ResponseHandlerOption
                        { ResponseHandler = nativeResponseHandler }));

            var responseMessage = nativeResponseHandler.Value as HttpResponseMessage;
            var locationheader = responseMessage.Headers.Location.OriginalString;

As this falls under the polling of long running operations, this work is currently pending the resolution of microsoftgraph/msgraph-sdk-design#83. We'll close this issue for now to be tracked via #1366