Example code not working

[realjatinpandey]

I copy pasted the example code and it has tonnes of errors. Please update that according to latest version of Firebase. After fixing many errors myself, still there is an error,
items.map((i) => ChatMessage.fromJson(i.data)).toList()
this line is giving an error
Error: The argument type 'Map<String, dynamic> Function()'
can't be assigned to the parameter type 'Map<dynamic, dynamic>'.

• 'Map' is from 'dart:core'.

please update the example code and also tell me how to fix it

[realjatinpandey]

error was in my code, closed the issue.