metasploit-framework/test/hooks/array_to_s.rb

class Array
	@@to_s_reported = {}
	def to_s(*args)
		if(not @@to_s_reported[caller[0].to_s])
			$stderr.puts "HOOK: Array#to_s at #{caller.join("\t")}"
			@@to_s_reported[caller[0].to_s] = true
		end
		super(*args)
	end
end