The defining type for this typedef.
If the the type referred to by the reflectee is a function type
F, the result will be FunctionTypeMirror reflecting F
which is abstract and has an abstract method call whose
signature corresponds to F.
Returns true if this declaration is considered private
according to the Dart language specification.
Always returns false if this declaration
is a library.
Otherwise return false.
Returns true if this mirror reflects dynamic, a non-generic class or
typedef, or an instantiated generic class or typedef in the current
isolate. Otherwise, returns false.
Checks the assignability relationship, denoted by <=> in the language
specification. This is the type relationship tested on assignment in
checked mode.