Sends an HTTP GET request with the given headers to the given URL, which can be a Uri or a String, and returns a Future that completes to the body of the response as a String.
The Future will emit a ClientException if the response doesn't have a success status code.
For more fine-grained control over the request and response, use send or get instead.
Source
Future<String> read(dynamic url, {Map<String, String> headers});