Perform a safe (i.e. error-checked) HTTP GET request to an H2O cluster.
Perform a safe (i.e. error-checked) HTTP GET request to an H2O cluster.
This function validates that no CURL error occurred and that the HTTP response code is successful. If a failure occurred, then stop() is called with an error message. Since all necessary error checking is done inside this call, the valid payload is directly returned if the function successfully finishes without calling stop().