1. override
Future<Response> head(url, { Map<String, String> headers })

Sends an HTTP HEAD request with the given headers to the given URL, which can be a Uri or a String.

For more fine-grained control over the request, use send instead.

Source 

@override
Future<Response> head(dynamic url, {Map<String, String> headers}) =>
  _sendUnstreamed("HEAD", url, headers);