All handles are virtually blessed to IO::Handle

$ perl -e'STDOUT->autoflush(1)'
Can't locate object method "autoflush" via package "IO::Handle" at -e 
+line 1.
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That doesn't mean the module is loaded:

$ perl -e'(bless {}, "Foo::Bar")->doit()'
Can't locate object method "doit" via package "Foo::Bar" at -e line 1.
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