Opens a HTTP connection.
The HTTP method is specified in
method and the URL to use in
Host header for the request will be set to the value
url.host is an IP address, it will
still be used in the
Host header). This can be overridden through the
HttpClientRequest interface before the request is sent.
For additional information on the sequence of events during an HTTP transaction, and the objects returned by the futures, see the overall documentation for the class HttpClient.
Future<HttpClientRequest> openUrl(String method, Uri url);