The method map isnt defined for the class Object. flutter

//METHOD 1
//Include List<user>> in StreamBuilder 
//i.e It should be 
StreamBuilder <List<User>> ()
//not just 
StreamBuilder ()

METHOD 2
//Change the variable to "dynamic" instead of "final" or "var"
//E.g 
dynamic users = snapshot.data!; 
//instead of 
final users = snapshot.data!;

dynamic canvasOrImg = querySelector('canvas, img');
var width = canvasOrImg.width;