isStatic property Null safety
true if this element is a static variable, as per section 8 of
the Dart Language Specification:
A static variable is a variable that is not associated with a particular instance, but rather with an entire library or class. Static variables include library variables and class variables. Class variables are variables whose declaration is immediately nested inside a class declaration and includes the modifier static. A library variable is implicitly static.
bool get isStatic;