HttpClient should not create a buffer for response contents on HeadOb…

…ject method

src/SwiftClient/SwiftClientObject.cs

@@ -24,7 +24,7 @@ public Task<SwiftResponse> HeadObject(string containerId, string objectId, Dicti
 
                 try
                 {
-                    using (var response = await _client.SendAsync(request).ConfigureAwait(false))
+                    using (var response = await _client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead).ConfigureAwait(false))
                     {
                         return GetResponse<SwiftResponse>(response);
                     }