Relax idler test.

Author: ioquatix

test/async/idler.rb

@@ -30,7 +30,7 @@
 		sleep 2.0
 
 		# Verify that the load is within the desired range:
-		expect(Fiber.scheduler.load).to be_within(0.2).of(0.5)
+		expect(Fiber.scheduler.load).to be_within(0.25).of(0.5)
 	end
 
 	it_behaves_like Async::ChainableAsync