async.gemspec in async-1.15.5 vs async.gemspec in async-1.16.0

@@ -17,14 +17,15 @@
 
 	spec.files         = `git ls-files`.split($/)
 	spec.executables   = spec.files.grep(%r{^bin/}).map{ |f| File.basename(f) }
 	spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
 	spec.require_paths = ["lib"]
-
+	
 	spec.required_ruby_version = ">= 2.2.7"
-
+	
 	spec.add_runtime_dependency "nio4r", "~> 2.3"
 	spec.add_runtime_dependency "timers", "~> 4.1"
+	spec.add_runtime_dependency "event", "~> 1.1"
 	
 	spec.add_development_dependency "async-rspec", "~> 1.1"
 	
 	spec.add_development_dependency "covered", "~> 0.10"