post function
Implementation
post(String url, dynamic data, Map<String, String> headers) async {
try {
var res = await http.post(Uri.parse(url), body: data, headers: headers);
if (res.statusCode == 200) {
return res.body;
} else if (res.statusCode == 404) {
throw NotFoundError("App not found(404).");
} else {
throw ExtraHTTPError(
"App not found. Status code ${res.statusCode} returned.");
}
} catch (e) {
rethrow;
}
}