A mirror on the owner of this Dart language entity. This is the declaration immediately surrounding the reflectee.
For a library, the owner is null.
For a class declaration, typedef or top level function
or variable, the owner is the enclosing library.
For a mixin application S with M, the owner is the owner
of M.
For a constructor, the owner is the immediately enclosing class.
For a method, instance variable or
a static variable, the owner is the immediately enclosing class,
unless the class is a mixin application S with M, in which case
the owner is M. Note that M may be an invocation of a generic.
For a parameter, local variable or local function the owner is the
immediately enclosing function.