|onFailure||Called when the request could not be executed due to cancellation, a connectivity problem or timeout. Because networks can fail during an exchange, it is possible that the remote server accepted the request before the failure.
|onResponse||Called when the HTTP response was successfully returned by the remote server. The callback may proceed to read the response body with Response.body. The response is still live until its response body is closed. The recipient of the callback may consume the response body on another thread.