Returns decoded data as Map, decoding it if not already decoded.
This method invokes decodedData and casts the decoded object as Map<String, dynamic>.
If there is no body data, this method returns null.
If decodedData does not produce a List that contains a single Map<String, dynamic> this method throws an
HTTPBodyDecoderException.
For a non-Future variant, see asMap.
Source
Future<Map<String, dynamic>> decodeAsMap() async {
await decodedData;
return asMap();
}