I used a simple and not so rigorous validator which also allows anything@string.com
and anything@string.co.in
domains:
var email = "tony123_90874.coder@yahoo.co.in";
bool emailValid = RegExp(r'^.+@[a-zA-Z]+\.{1}[a-zA-Z]+(\.{0,1}[a-zA-Z]+)$').hasMatch(email);
print (emailValid);